Bad service

Was contacted by Standard bank to use a debit order to pay my credit card. The debit order was supposed to start from Sep 2019. So this month I transferred money into my credit card as I used to do every month. On 5 Aug I noticed additional money paid into my account - source of payment unknown. On 6 Aug I contacted Standard bank Credit Account to enquire the source of the payment. They were unable to provide any info. On 8 Aug I received a SMS stating debit order returned unpaid. I again contacted the Credit Card department just be informed the debit order is from an account (NOT MY ACCOUNT and this so called account have been closed by myself) Now I have to pay additional funds into my account to reopen my Credit Card facility and extra cost not my fault for the returned debit order.