diff --git a/app/models/customer.rb b/app/models/customer.rb
index b6560bab2d77..16fd8da65f4c 100644
--- a/app/models/customer.rb
+++ b/app/models/customer.rb
@@ -71,6 +71,7 @@ class Customer < ApplicationRecord
   scope :falling_back_to_default_dunning_campaign, -> {
     where(applied_dunning_campaign_id: nil, exclude_from_dunning_campaign: false)
   }
+  scope :with_dunning_campaign_not_completed, -> { where(dunning_campaign_completed: false) }
 
   validates :country, :shipping_country, country_code: true, allow_nil: true
   validates :document_locale, language_code: true, unless: -> { document_locale.nil? }
diff --git a/app/models/dunning_campaign.rb b/app/models/dunning_campaign.rb
index abaff0760c61..b8f0ca6444d8 100644
--- a/app/models/dunning_campaign.rb
+++ b/app/models/dunning_campaign.rb
@@ -33,17 +33,20 @@ def self.ransackable_attributes(_auth_object = nil)
 
   def reset_customers_last_attempt
     # NOTE: Reset last attempt on customers with the campaign applied explicitly
-    customers.update_all( # rubocop:disable Rails/SkipsModelValidations
+    customers.with_dunning_campaign_not_completed.update_all( # rubocop:disable Rails/SkipsModelValidations
       last_dunning_campaign_attempt: 0,
       last_dunning_campaign_attempt_at: nil
     )
 
     # NOTE: Reset last attempt on customers falling back to the organization campaign
     if applied_to_organization?
-      organization.customers.falling_back_to_default_dunning_campaign.update_all( # rubocop:disable Rails/SkipsModelValidations
-        last_dunning_campaign_attempt: 0,
-        last_dunning_campaign_attempt_at: nil
-      )
+      organization.customers
+        .falling_back_to_default_dunning_campaign
+        .with_dunning_campaign_not_completed
+        .update_all( # rubocop:disable Rails/SkipsModelValidations
+          last_dunning_campaign_attempt: 0,
+          last_dunning_campaign_attempt_at: nil
+        )
     end
   end
 end
diff --git a/spec/models/dunning_campaign_spec.rb b/spec/models/dunning_campaign_spec.rb
index 0c89e92877fe..e42c48e880d6 100644
--- a/spec/models/dunning_campaign_spec.rb
+++ b/spec/models/dunning_campaign_spec.rb
@@ -64,6 +64,19 @@
         .and change { customer.last_dunning_campaign_attempt_at }.from(last_dunning_campaign_attempt_at).to(nil)
     end
 
+    it "does not reset last attempt on customers with dunning campaign already completed" do
+      customer = create(
+        :customer,
+        organization:,
+        applied_dunning_campaign: dunning_campaign,
+        last_dunning_campaign_attempt: 1,
+        dunning_campaign_completed: true
+      )
+
+      expect { dunning_campaign.reset_customers_last_attempt }
+        .not_to change { customer.reload.last_dunning_campaign_attempt }.from(1)
+    end
+
     context "when applied to organization" do
       subject(:dunning_campaign) { create(:dunning_campaign, applied_to_organization: true) }
 
@@ -79,6 +92,18 @@
           .to change { customer.reload.last_dunning_campaign_attempt }.from(2).to(0)
           .and change { customer.last_dunning_campaign_attempt_at }.from(last_dunning_campaign_attempt_at).to(nil)
       end
+
+      it "does not reset last attempt on customers with dunning campaign already completed" do
+        customer = create(
+          :customer,
+          organization:,
+          last_dunning_campaign_attempt: 2,
+          dunning_campaign_completed: true
+        )
+
+        expect { dunning_campaign.reset_customers_last_attempt }
+          .not_to change { customer.reload.last_dunning_campaign_attempt }.from(2)
+      end
     end
   end
 end