TELKOM MOBILE

I have been overcharged for the past 7 months or so on my account. I have contacted client services numerous times. It was indicated that my previous contract had not been deactivated, so in fact I am being charged for x2 contracts on my x1 number. This has been rectified now. I have not received any REFUND for being overcharged. The funds need to be credited to my BANK ACCOUNT as I need that money. No credited towards my mobile account. I am now into a minus on my bank account & other payments because of this. It is affecting my credit record. Please can someone advise me on this & payment into my bank account?? I have the case number, etc. Thank you