diff --git a/app/services/concerns/waste_carriers_engine/can_merge_finance_details.rb b/app/services/concerns/waste_carriers_engine/can_merge_finance_details.rb
index a2421d5ea..a2aa7e8b9 100644
--- a/app/services/concerns/waste_carriers_engine/can_merge_finance_details.rb
+++ b/app/services/concerns/waste_carriers_engine/can_merge_finance_details.rb
@@ -13,7 +13,7 @@ def merge_finance_details
       end
 
       while transient_registration.finance_details.payments.present?
-        registration.finance_details.payments << transient_registration.finance_details.payments.shift
+        registration.finance_details.payments << transient_registration.finance_details.payments.first
       end
 
       registration.finance_details.update_balance