Struggling to get a refund

MTN call centre and service sucks. Ive struggled to cancel a contact with them for most of last year. I took out a contract telephonically in February 2018. When the phone arrived it was not the phone I expected and took the phone back within five days as per their intruction. I have struggled to get this contract cancelled and eventually got it right in November 2018. Meanwhile they have been deducting money from my bank account from April- November. I have been struggling to get this money back since then. I have made numerous calls to the call centre with no results. This is ridiculous. I am at my witts end! I am only giving a one strar rating since the system does not allow me to give a 0. I have been a loyal MTN customer since 1998 but this incident really make me view them in a different light. I cant wait for my other contracts to expire so I can go ellsewhere.