8ta has bad service_settled account handed over

I bought a blackberry phone back in 2011 on contract from 8ta East Rand. it started off with fluctuating amounts to non being debited from my account and sometimes debit orders not running on time and that in turn reflects bad to me and my credit record. Finished the contract in 2 years but a year later got a call from 8ta, they told me that i was in areas, areas that i know nothing about, areas that could have been disclosed when the 24 month contract lapsed. I then did internet transfer and phoned in to confirm that the R175 (cant remember the exact amount) has been transferred, case closed. Again, i received a call from the debt-collectors telling me that the account has been handed over and i owe them an amount of R2000 which i just don't get because my account was paid off. Telkom 8ta offers very bad service and i am not happy at all...