AVOIDING TO REFUND ME

Ref no: *** African bank promised me 20% if I settle my account ending with 005 on the 2/09/2020 I went to the branch to pay up this account, when I get there they called their head office for me to talk to them and get settlement amount. the consultant worked out the number and gave it to the lady in the branch, I settle that amount via EFT. When I get home I calculated the given percentage and found out that it was not a promised 20% but only 0.05%, I went back to the branch to query the given discount percentage. they call head office again this time I spoke to Rebecca Kekana, she put me on hold to discuss with supervisor, she came back and told me that they made mistake they will refund me, she lodge refund for me with above ref number. on the 03/09/20 I got sms which read as follows "Hello Mr Tota. We are sorry we cannot complete your request because of Bank charges do not reflect on thr bank statement for acc ref ***, your number ***. I called again on the number provided on the sms because I did not understand what bank charges has to do with discount. I was told the notes on the system require that I send ID proof of payment and my bank. I send those documents as requested on the 3/09/20. on 7/09/20 I got another sms which read as follows" Hello Mr Tota .We are sorry we cannot complete your request because No credit balance on the requested account ref ***. I called again because the settled account is not the one ending with 002 and I was told the consultant made an error with account, this person this time around told me she is correcting this and escalating to her supervisor. I WANT TO KNOW WHY SO MANY ERRORS. STARTING WE PERCENTAGE CALCUALTIONS WHICH THEY ADMIT, NOW THIS MIXING ACCOUNTS NUMBER ? IS THE BANK TRYING TO DELAY THE REFUND AND THEY DONT WANT TO REFUND IF SO THEY SHOUD JUST TELL ME. IM SPENDING LOTS OF TIME AND MONEY CALLING PEOPLE WH SEEM TO BE COMPLETELY INCOMPETANT??