Unfair Practice

My account (A***)was in arrears and handed over to VVM, i continued to pay them. I then requested a settlement discount and enquired whether my numbers can be converted to Prepaid. I paid the settlement figure and went to the Cell shop to get a simswap towards end October, they told me i can not get prepaid cards because the contact expires on 15 November and i had to get contract cards. My account was suspended for quite a few months and some data and minute should have accumulated during suspension, and i was going to use that till 15/11/20. Mid November MTN send me a bill for R1400.00, when i enquired about this and the fact that i settled, they dont give me proper answers. According to me this contract is settled and i should be able to convert to Prepaid.