AIB Merchant Services (AIBMS) has said it will refund thousands of customers who may have been debited twice for transactions after using AIB merchant point of sale terminals earlier this week.

More than 80,000 transactions were carried out through these terminals on Monday. The firm became aware of the error, which was caused by a technical issue at a processing facility in Germany, on Wednesday, but said it had since been resolved.

The merchants where the affected terminals are in place were also credited twice.

AIBMS is a joint venture between international electronic commerce and payment services firm First Data Corporation and AIB. First Data processes AIBMS transactions.

AIBMS said it was working to ensure customers were reimbursed promptly and apologised for any inconvenience caused. Refunds are expected in the coming days.

“The money will go back in to customers’ accounts automatically but if they want to double check they can contact their branch,” a spokeswoman said.

For further information, customers can contact 0818 724 724 or their local AIB branch. Cardholders should contact their issuing bank, who will confirm if the credit has been posted to their account.