Disappointed

My dad has been having problems with mtn the past 3 months, everymonth by the 20th the phone gets suspended, we contact the mtn and ask why, they tell them we make payments before the 7th as he is a pensioner, they told my dad the phone gets suspended there is another simcard we told them that we do not have another simcard, spoke to Christian Webster who promise to help but he never got back and then i spoke to another Teamleader who look like he knows what he do, and he investigate and found out this simcard is a card that was given in 2018 and it came with the device,,we told him we don't have that card and never use it and why when we upgrade in August the consultant did not informed us and that simcard should be canceled.this Teamleader also just dissappear. Today 21 December, called again because the phone is suspended again insist on speaking to a manager because we are tired of saying the same thing. Spoke to a manager she had no interest in helping me, they way she talk shows whatever i says doesn't matter. I believe that manager should be willing to go the extra mile and are also willing to to help. I'm disappointed in the whole team. All i want is for the simcard to be cancel and mtn to stop suspended the simcard the 20th. Contact number ***