Poor customer service

I have had the worst experience with this company, when I entered into a phone agreement with them we agreed on R300 premiums for 5 months on average they debited R800 reasoning I was exceeding their limits even when I was no longer using their sim card . Fast forward last month I decided to settle the account to end my relationship with them they over quoted me and I paid that amount after noting they over quoted me instead of refunding me they are giving me run arounds asking me for bank statements whereas they've been debiting the same account over 6 months. Still haven't received my refund and all staff is clueless(called over 5 times already). Will never recommend this company to anyone