diff --git a/src/common/modules/otp/repositories/otp.repository.ts b/src/common/modules/otp/repositories/otp.repository.ts
index 879a6f8..f9d13f9 100644
--- a/src/common/modules/otp/repositories/otp.repository.ts
+++ b/src/common/modules/otp/repositories/otp.repository.ts
@@ -2,7 +2,7 @@ import { Injectable } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
 import { MoreThan, Repository } from 'typeorm';
 import { Otp } from '../entities';
-import { IVerifyOtp } from '../interfaces';
+import { ISendOtp, IVerifyOtp } from '../interfaces';
 const FIVE = 5;
 const SIXTY = 60;
 const ONE_THOUSAND = 1000;
@@ -42,4 +42,18 @@ export class OtpRepository {
   updateOtp(id: string, data: Partial<Otp>) {
     return this.otpRepository.update(id, data);
   }
+
+  invalidateOtp(otp: ISendOtp) {
+    return this.otpRepository.update(
+      {
+        userId: otp.userId,
+        scope: otp.scope,
+        otpType: otp.otpType,
+        isUsed: false,
+      },
+      {
+        isUsed: true,
+      },
+    );
+  }
 }
diff --git a/src/common/modules/otp/services/otp.service.ts b/src/common/modules/otp/services/otp.service.ts
index 51f6dad..01ebb79 100644
--- a/src/common/modules/otp/services/otp.service.ts
+++ b/src/common/modules/otp/services/otp.service.ts
@@ -15,8 +15,11 @@ export class OtpService {
     private readonly otpRepository: OtpRepository,
     private readonly notificationService: NotificationsService,
   ) {}
-  private useMock = this.configService.get<boolean>('USE_MOCK', false);
+  private useMock = [true, 'true'].includes(this.configService.get<boolean>('USE_MOCK', false));
   async generateAndSendOtp(sendOtpRequest: ISendOtp): Promise<string> {
+    this.logger.log(`invalidate OTP for ${sendOtpRequest.recipient} and ${sendOtpRequest.otpType}`);
+    await this.otpRepository.invalidateOtp(sendOtpRequest);
+
     this.logger.log(`Generating OTP for ${sendOtpRequest.recipient}`);
     const otp = this.useMock ? DEFAULT_OTP_DIGIT.repeat(DEFAULT_OTP_LENGTH) : generateRandomOtp(DEFAULT_OTP_LENGTH);
 
diff --git a/src/customer/dtos/response/customer-response.dto.ts b/src/customer/dtos/response/customer.response.dto.ts
similarity index 95%
rename from src/customer/dtos/response/customer-response.dto.ts
rename to src/customer/dtos/response/customer.response.dto.ts
index 04c849e..3d40cf7 100644
--- a/src/customer/dtos/response/customer-response.dto.ts
+++ b/src/customer/dtos/response/customer.response.dto.ts
@@ -55,6 +55,9 @@ export class CustomerResponseDto {
   @ApiProperty()
   isGuardian!: boolean;
 
+  @ApiProperty()
+  waitingNumber!: number;
+
   @ApiPropertyOptional({ type: DocumentMetaResponseDto })
   profilePicture!: DocumentMetaResponseDto | null;
 
@@ -76,6 +79,7 @@ export class CustomerResponseDto {
     this.gender = customer.gender;
     this.isJunior = customer.isJunior;
     this.isGuardian = customer.isGuardian;
+    this.waitingNumber = customer.waitingNumber;
 
     this.profilePicture = customer.profilePicture ? new DocumentMetaResponseDto(customer.profilePicture) : null;
   }
diff --git a/src/customer/dtos/response/index.ts b/src/customer/dtos/response/index.ts
index be77608..16eaeba 100644
--- a/src/customer/dtos/response/index.ts
+++ b/src/customer/dtos/response/index.ts
@@ -1,3 +1,3 @@
-export * from './customer-response.dto';
+export * from './customer.response.dto';
 export * from './internal.customer-details.response.dto';
 export * from './internal.customer-list.response.dto';
diff --git a/src/customer/entities/customer.entity.ts b/src/customer/entities/customer.entity.ts
index 4c7b6ea..48be217 100644
--- a/src/customer/entities/customer.entity.ts
+++ b/src/customer/entities/customer.entity.ts
@@ -3,6 +3,7 @@ import {
   Column,
   CreateDateColumn,
   Entity,
+  Generated,
   JoinColumn,
   OneToOne,
   PrimaryColumn,
@@ -67,6 +68,10 @@ export class Customer extends BaseEntity {
   @Column('boolean', { default: false, name: 'is_guardian' })
   isGuardian!: boolean;
 
+  @Column('int', { name: 'waiting_number' })
+  @Generated('increment')
+  waitingNumber!: number;
+
   @Column('varchar', { name: 'user_id' })
   userId!: string;
 
@@ -101,9 +106,9 @@ export class Customer extends BaseEntity {
   @JoinColumn({ name: 'civil_id_back_id' })
   civilIdBack!: Document;
 
-  @CreateDateColumn({ type: 'timestamp with time zone', default: () => 'CURRENT_TIMESTAMP' })
+  @CreateDateColumn({ type: 'timestamp with time zone', default: () => 'CURRENT_TIMESTAMP', name: 'created_at' })
   createdAt!: Date;
 
-  @UpdateDateColumn({ type: 'timestamp with time zone', default: () => 'CURRENT_TIMESTAMP' })
+  @UpdateDateColumn({ type: 'timestamp with time zone', default: () => 'CURRENT_TIMESTAMP', name: 'updated_at' })
   updatedAt!: Date;
 }
diff --git a/src/db/migrations/1742112997024-update-customer-table.ts b/src/db/migrations/1742112997024-update-customer-table.ts
new file mode 100644
index 0000000..481bee7
--- /dev/null
+++ b/src/db/migrations/1742112997024-update-customer-table.ts
@@ -0,0 +1,36 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+export class UpdateCustomerTable1742112997024 implements MigrationInterface {
+  name = 'UpdateCustomerTable1742112997024';
+
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+            ALTER TABLE "customers"
+            RENAME COLUMN "createdAt"
+            TO "created_at"
+          `);
+
+    await queryRunner.query(`
+            ALTER TABLE "customers"
+            RENAME COLUMN "updatedAt"
+            TO "updated_at"
+          `);
+    await queryRunner.query(`ALTER TABLE "customers" ADD "waiting_number" SERIAL NOT NULL`);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`ALTER TABLE "customers" DROP COLUMN "waiting_number"`);
+
+    await queryRunner.query(`
+            ALTER TABLE "customers"
+            RENAME COLUMN "created_at"
+            TO "createdAt"
+          `);
+
+    await queryRunner.query(`
+            ALTER TABLE "customers"
+            RENAME COLUMN "updated_at"
+            TO "updatedAt"
+          `);
+  }
+}
diff --git a/src/db/migrations/index.ts b/src/db/migrations/index.ts
index 50a4852..9ca8914 100644
--- a/src/db/migrations/index.ts
+++ b/src/db/migrations/index.ts
@@ -23,3 +23,4 @@ export * from './1739868002943-add-kyc-status-to-customer';
 export * from './1739954239949-add-civilid-to-customers-and-update-notifications-settings';
 export * from './1740045960580-create-user-registration-table';
 export * from './1741087742821-add-used-flag-to-otp-and-remove-constraints-from-customers';
+export * from './1742112997024-update-customer-table';