Inform the concerned bank. According to the Thai Bankers Association guidelines, obligatory timeframes in dealing with this issue are:
Because of technical errors at the bank’s end, the bank will investigate, notify and solve the case within 3 days.
In case if submitted a wrong amount or a wrong account number; when both parties are at the same bank, the case will be verified and notified to the customers within 15 days. If the recipient is of other bank, the process would take 20 working days.