Cell c service disappointing

I had a contract at cell c it was in arrears for a few months. When I wanted to make a payment I had to wait on the line forever. They sent me emails with link on which I could make a payment, but immediately the arrears amount was doubled. I finally reached the firm to which my account was handed over. Then I made a payment. The next month when I wanted to make a payment again they said my account isnt with them anymore. I'm struggling to find someone to contact me. I called in again and the consultant gave me email addresses as she wasn't sure what to do. I sent emails to all the addresses from which to email addresses did not exist. I'm worried because next time I reach them I will probably have to pay triple the amount.