diff --git a/apps/api/src/contacts/merge-same-mobile.ts b/apps/api/src/contacts/merge-same-mobile.ts
index bc82304..7c9c041 100644
--- a/apps/api/src/contacts/merge-same-mobile.ts
+++ b/apps/api/src/contacts/merge-same-mobile.ts
@@ -26,6 +26,9 @@ const personSelect = {
   companyId: true,
   customFields: true,
   importSource: true,
+  sourceRef: true,
+  previousImportSource: true,
+  previousSourceRef: true,
   loyaltyPoints: true,
   discLabel: true,
   discReliable: true,
@@ -62,6 +65,8 @@ function mergedFields(keeper: PersonRow, extras: PersonRow[], canon: string): Pr
   let showGenderInName = keeper.showGenderInName;
   let previousFirstName = keeper.previousFirstName;
   let previousLastName = keeper.previousLastName;
+  let previousImportSource = keeper.previousImportSource;
+  let previousSourceRef = keeper.previousSourceRef;
   let discLabel = keeper.discLabel;
   let discReliable = keeper.discReliable;
   let discAssessedAt = keeper.discAssessedAt;
@@ -93,6 +98,14 @@ function mergedFields(keeper: PersonRow, extras: PersonRow[], canon: string): Pr
     if (blank(previousLastName) && extra.previousLastName) {
       previousLastName = extra.previousLastName;
     }
+    if (
+      blank(previousImportSource) &&
+      extra.importSource &&
+      extra.importSource !== keeper.importSource
+    ) {
+      previousImportSource = extra.importSource;
+      previousSourceRef = extra.sourceRef;
+    }
     if (
       keeper.importSource === 'tahesab' &&
       blank(previousFirstName) &&
@@ -134,6 +147,8 @@ function mergedFields(keeper: PersonRow, extras: PersonRow[], canon: string): Pr
     showGenderInName,
     previousFirstName,
     previousLastName,
+    previousImportSource,
+    previousSourceRef,
     discLabel,
     discReliable,
     discAssessedAt,
diff --git a/apps/api/src/contacts/same-mobile-merge.service.ts b/apps/api/src/contacts/same-mobile-merge.service.ts
index 907bfeb..bed1c1e 100644
--- a/apps/api/src/contacts/same-mobile-merge.service.ts
+++ b/apps/api/src/contacts/same-mobile-merge.service.ts
@@ -2,7 +2,7 @@ import { Injectable, Logger, type OnApplicationBootstrap } from '@nestjs/common'
 import { PrismaService } from '../prisma/prisma.service';
 import { mergeSameMobilePeople } from './merge-same-mobile';
 
-const FIX_KEY = 'person-mobile-canonical-v2';
+const FIX_KEY = 'person-mobile-canonical-v3';
 
 @Injectable()
 export class SameMobileMergeService implements OnApplicationBootstrap {
diff --git a/apps/api/src/integrations/tahesab/person-link.service.ts b/apps/api/src/integrations/tahesab/person-link.service.ts
index 7cdda80..21c74df 100644
--- a/apps/api/src/integrations/tahesab/person-link.service.ts
+++ b/apps/api/src/integrations/tahesab/person-link.service.ts
@@ -601,6 +601,7 @@ export class TahesabPersonLinkService {
     const sourceRef = String(dto.moshtariCode);
 
     let personId = dto.personId;
+    let preserveExistingLink = false;
     if (personId) {
       const existing = await this.getPerson(organizationId, personId);
       const prevFirst = existing.firstName;
@@ -629,21 +630,28 @@ export class TahesabPersonLinkService {
       });
     } else {
       // اگر موبایل تکراری است → همان شخص؛ نام قبلی حفظ و نام ته‌حساب جایگزین.
-      // شخصی که روی همین اتصال به کد دیگری لینک است کنار گذاشته می‌شود؛
-      // وگرنه upsert لینک، کد قبلی را جابه‌جا و آن مشتری را دوباره «واردنشده» می‌کند.
+      // اگر همان شخص قبلاً به کد دیگری از این اتصال لینک شده، لینک جابه‌جا نمی‌شود
+      // تا کد قبلی دوباره «واردنشده» نشود و مشتری تکراری ساخته نشود.
       const mobileKeys = phoneIdentityKeys(mobile);
       const matches = mobileKeys.length
         ? await this.prisma.person.findMany({
             where: {
               organizationId,
               OR: [{ mobile: { in: mobileKeys } }, { phone: { in: mobileKeys } }],
-              accountingLinks: { none: { connectionId: dto.connectionId } },
+            },
+            include: {
+              accountingLinks: {
+                where: { connectionId: dto.connectionId },
+                select: { moshtariCode: true },
+              },
             },
             orderBy: { createdAt: 'asc' },
           })
         : [];
       const byMobile = matches.find((person) => person.importSource === 'tahesab') ?? matches[0] ?? null;
       if (byMobile) {
+        const linkedCode = byMobile.accountingLinks[0]?.moshtariCode;
+        preserveExistingLink = linkedCode != null && linkedCode !== dto.moshtariCode;
         const nameChanged =
           `${byMobile.firstName} ${byMobile.lastName}`.trim() !==
           `${firstName} ${lastName}`.trim();
@@ -662,7 +670,7 @@ export class TahesabPersonLinkService {
               : {}),
             ...carryPreviousSource(byMobile, 'tahesab'),
             importSource: 'tahesab',
-            sourceRef,
+            sourceRef: preserveExistingLink ? String(linkedCode) : sourceRef,
             ...(!byMobile.birthDate && pickBirthDate(row) ? { birthDate: pickBirthDate(row) } : {}),
             ...canonicalMobileUpdate(mobile, byMobile),
           },
@@ -688,6 +696,32 @@ export class TahesabPersonLinkService {
       }
     }
 
+    if (preserveExistingLink) {
+      await this.applyTahesabGroup(organizationId, dto.connectionId, personId, row);
+      const existing = await this.prisma.personAccountingLink.findFirst({
+        where: { personId, connectionId: dto.connectionId },
+        include: {
+          connection: { select: { label: true, dbName: true, isDefault: true } },
+        },
+      });
+      if (!existing) {
+        throw new NotFoundException('لینک ته‌حساب این مشتری یافت نشد.');
+      }
+      if (!options?.skipJob) {
+        await this.prisma.accountingSyncJob.create({
+          data: {
+            organizationId,
+            connectionId: dto.connectionId,
+            kind: 'import',
+            status: 'success',
+            request: dto as unknown as Prisma.InputJsonValue,
+            result: { personId, linkId: existing.id, keptLink: true } as Prisma.InputJsonValue,
+          },
+        });
+      }
+      return { personId, link: this.linkDto(existing) };
+    }
+
     const link = await this.prisma.personAccountingLink.upsert({
       where: {
         personId_connectionId: {