Cell c ****med me 10k

I had a cellphone contract with cell c which went into arrears as I lost my job due to covid 19 lockdown, I was later reinstated at work and called them immediately to make arrangements, the balance was around 10k, they told me my account has been handed over to nimble collections services which I called and made arrangements with them until I totally paid off the balance, it's been two months since I cleared the balance but am still listed with the same balance of 10k, when I call cell c they tell me they account is with nimble so they can't clear my name, when I call nimble they say I was listed by cell c so they can't assist, now am not understanding why I paid off the account, I threw 10k away in this tough economic times, everytime I write a review cell c promises to call and resolve my issue but they never do, worse case is that am working for a bank and am not allowed to be listed and I've explained that several times but they don't seem to care, my advise to you is stay away as far as you can from doing any business with cell c