Cell C
Sending me messages that im overdue

I am very disappointed in Cell C's customer service. I pay every month via EFT using my cell number as reference. Im getting messages that im overdue and when I call Cell C they tell me I need to fax my proof of payment every month. whats the use of putting my cell number as a reference if they going to use my money as charity money and not allocate it to my account. They switching off my phone because of this and I have emailed proof of payments to [Email Removed] and still nothing