money transfered from my account

I made arrangement with their attorneys that i will be able to pay R250.00 every month since i am no longer working and i have been keeping to this promise until last month i paid 2 days later than the expected day.On the 6th of June R1200 was taken from my account from the load department and when i call them they could see that i paid on the second but yet they took out thee money and i have requested the refund but till today i have not yet received anything from them.I have specifically told them that i am a student now i will be able to pay the certain amount but now they just do as they want in my account and it was not for the fist time,I cant just pay for one thing in a month twice.