R3000 debited *******ly

I requested a settlement amount to end cell contract and migrate number. They provided me with amount and banking details. I paid sent proof and they moved my number to prepaid, I migrated to telkom fine. One month later they debited my account for that same amount I had already paid. I have contacted numerous times for months now, everytime they promise to refund me, but still nothing. They phone every month to try sell me a new contract but sales people not interested at all about my outstanding money.