Telkom Bad Service

Hello Peter, i have had bad experience with telkom, it seems telkom does not know how to bill its customers, i took a contract phone with them in 2014 and settled the account in 2017, in 2017 they offered me with 3G router contract, which i took it, it was supposed to be a capped line, and i was supposed to pay R100 every month, at the end of the first month, the statement came and said i owe them R600, i disputed that and no one came back to me, i then asked them to come to my place to collect their router, and no one came, i decided not to pay them, they handed over my account to debt collectors, and this was affected my credit score badly, i decided to pay this account which i never used its data, and settled it in 2019, late last year i received an sms from different collectors saying i owe telkom R2800, when i contact telkom to enquire about this, they say i owe them for a contract i took in 2014, as far i am concerned, that 2014 contract i settled in 2017, and i am listed again on credit bureau as bad payer, i am currently trying to apply for vehicle finance and home loan from all banks, i get declined because of this.