Vodacom ruined my credit score!!!!

I am soo annoyed by Vodacom.On the 16th of April 2022 I went to Vodacom to settle and cancel my account,the lady who assisted me gave me an amount that I should pay to settle my account,I paid the money in-store,I asked the lady of there won't be any amount to pay after I have paid that amount and she said no.

After 3 months of settling my account I called Vodacom asking for paid up letter since the account had been showing on my credit bureau to my surprise I was told my account has been handed over due to non payment,I asked them how come,I was informed that by the time I was settling my account they already issues an invoice for April so the money I paid to settle my account did not include April amount and no one informed me about that.

I have never even single day received a communications from Vodacom telling me that I am owing them,but they handed me over,now everything is a mess my credit score is very bad,I don't qualify for anything because of their incompetency.