Dispute of the Spend limit unauthorized

I have a contract with MTN combining WIFI and my contract phone from 09/Sep i have been communicating with them but with no success. my spend limit was increased and i happen to owe them with out my knowledge. i call them on the 09/Sept trying to understand how they explain to me the term SEND LIMIT which i didn't know first ref i logged disputing this is *** when i made follow up second ref: *** on the 26 Sep until today no feedback from it. I patiently called again on 06/10/2022 Olona assisted me and i requested a teamleader to call me because my dispute hasn't been solve until the 11/11/2022 my last call i spoke with Zandile Mkhize who said maybe ********** called me and i gave them my OPT and they were able to increase my limit if i wasn't the one who did it even though the is no call she say was made to increase that "SPEND LIMITE" my credit record is affected in all of this and when she check she says my Account has been in arrears for 90days which i don't know why.....MTN i am highly stressed and disappointed with your service