Incompetence causing bad credit score

I paid my account in full in July 2021 after it was sent to their Legal Department. For months I called to clear the account and nothing happened and I got tired and left it like that. Now I'm getting calls from MBD to pay this account. I do not owe Vodacom and even their machine when I put the cell number says so. Now my name is in the dumps at Clearscore too because of their incompetence and I don't know where to go from here.