MTN Bull**** service

Hi I have a big issue with MTN I took out a contract with MTN in February 2020 with 2 phones A10S & A30s with 2 sim cards Sim card *******35707 we use on number *** Sim card *******35699 number *** we do use at all and this card was activated by MTN not even by myself , i do not use this card now i have to pay something i do use and was activated by me, why did they not keep the card un-active i dont mind paying for the card which is way less Now my account are arrears for something i do not use this really bad and not good service i need a answer my number ***