Poor customer service

We are having a serious problem with MTN. My husband Kholofelo Kingsley Tlou Id *** , MTN NUMBER 7808 had contract with MTN from 2018 May which expired May 2020. During May 2020 he personally went to local MTN at Phola Park to request cancelation of contract because the service was paid up. Then they did not cancel the contract instead they were continuing billing him. m My husband was doing the reversal of their debit orders since their service expired. now we are in the process of purchasing a house and we find out that MTN took him to default data. My husband went to MTN Phola park on Monday 24 to request them to cancelation and paid up letter. People from local MTN told him to call customer care. He even emailed them , then Mr NGWENYA said for him to get assistant must write a letter and email it to ***. we did that yesterday. Now when they respond the email they say he must call 135 of which is something that he did before and they failed to help him. We are so frustrated because we are in the process of purchasing a house but the process can not be processed because MTN. We urgently request hellopeter team to intervein on matter. Thank you. K.K TLOU CONTACT ***