Rain is *****ing money

Rain is a bunch of ********s, last months I changed my billing date to the 1st, then money was deducted R625 on the 25th which i paid the 26th( thinking my billing date wasn't changed cause i didn't receive any confirmation) then on the 1st of November another R625 was deducted from my account only 5 days after, so i contacted rain asking whats going on, the guy told me i infact did change my installment date and thats the reason it went of again, but, i am now in credit and end the 1st of December they will only take pro rata anount for 7 days, comes 1st December and they try and deduct R625 again, and I've been calling them endlessly and they keep on saying the billing department will call me back and they never do, i have emptied my bank account and will not pay until its sorted out