CELL C STOLE R27500 FROM ME

My account was handed over by Cell c, i have paid them a settlement amount of R27500 4 months ago, since then my account has not been updated and they still semd me letters saying that i owe them R27500 i have se t them my proof of payment to the company i paid the money to and they confirmed that thet did receive the money.

Its been 4 months now and im still in arreers with them even though i paid every sent i owed them