Poor Customer Service and Don't care attitude

I accidentally paid R2700 into my Cell C Account instead of my Bank Account. I have been sent from pillar to post to get my money back. They confirmed 7 days, but after more than 14 days give me the run around. I spoke to Robin, Mpho, Cindy and Sindiswa some of who cut me off on purpose and then at the end told me my case has been closed. This without paying me back. My account is not in arrears but they then proceed to take off my next payment which is only due at the end of the month, which leaves me with less than the R2700 paid in error. I am sure they will then debit me again on the due date. They asked me to send proof of the payment together with Bank Statements which I have done. I have to answer security questions every time I call them because they never call back. I keep being told that I must wait for 48 hours and then after 48 hours I call them and then I get told to send documents that I already sent. I have been unable to put petrol in my car or get medication that is chronic. I know the initial error was mine, but for them to be so unprofessional and uncaring is very disappointing and unprofessional. I called them on the 24th February. I sent documents on the26th as it took them 2 days to ask it. Today is the 15th March, I am still struggling to get my money and they said they will reopen the call and it will take another 48 hours for them to revert. 😒Cell C -Don't Care Service for Customers!! I will not renew my contract with them.