Threaten to blaclist but account paid

My son had a student account with Standard Bank which I (Private Banking Client) signed surety for. I settled the account after it took us about 4 weeks to get the correct balance. Then we were told he needs to go to the bank to close the account, which he did and still after I was told this is the final balance, we had to pay additional fees. This week he gets SMS threaten him that they going to backlist him as the account is in arrears. He phoned the call centre (also a joke to call them) and was told system error they cannot see what is wrong but will fix. Today another SMS. How do you do business. I have all my accounts with Standard Bank as a Private Banking client, and I must say it is time to move everything to a proper bank. My son and daughter will also move accounts and my investments is being transferred as well. Can somebody sort this account out as if he gets Blacklisted by error, he will lose his approval for renting a house and I will personally sue Standard Bank.

Please behave like a Bank and sort this out today!!!! I have provided my sons mobile number. I will also make my Private Banker aware that die to this she must get my transfer of accounts and investments ready, unless you prrof to me you serious about business and sort this out