Unprofessional Debt Settlement

On the 07/01/16 my husband phoned the Standard Bank credit card department to get the full settlement amount due on his account. The amount was sent to him via email & we then proceeded to do a cash deposit on the 08/01/16 directly into the credit card account number as stated on the email. He then requested a settlement letter on the same day confirming that the account was paid in full & thereafter closed, which he received on the 15th. I would also like to make mention that every other creditor that my husband settled his accounts with sent an extremely professional settlement letter. Standard Banks letter contains one sentence on a letterhead. Today my husband receives a statement via email now stating that there is a cash deposit fee of R311.74 still outstanding on his account. We were NEVER advised that there would be a deposit fee charged to the credit card account after settling & were not charged for this on any other creditor account! We have the letter stating that the account has been settled in full & that the account has now been closed. How can Standard Bank send a letter confirming this, then send a statement two days later. UNPROFESSIONAL & NO ETIQUETTE!