angry ? customer

hi there on the 29th Sept 2018 i made a payment to cellc at westwood mall cellc the sum of R9060'60 it was a commitment and usage fee closing all my contracts n migrated it to prepaid now cellc call centre are billing to say i need to pay again cos they lost my payment i phoned them like 6 times they still telling me the same i email proof if payment the the cellc store faxed my payment to them they still saying they cant find payment i got proof of payment n the store got my paperwork so please if u can help me cellc wants to rip me off i cant afford to pay that amount again n they threatening to debit my capitec acc i like to knw hw they got my capitec acc number if they didnt receive my payment cos i use to use absa acc for cellc debits n when i paid dem of on 29th sept 2018 with my capitec bank acc n tranfer muny to cellc pls help me thanx