Require payment or reactivation

I am not happy with Rain,I am fuming right now because I paid R529 last week Saturday which is on the 25th then on Monday the 27th I called and asked to change my payment date to the 1st of every month. This morning I received an sms from them that I should pay another R529 like I get it from the tree. I then tried calling them to ask for a refund so I can pay again cos I really and honestly won't pay another R529 when I paid last week but no one answered my call.