Debit order disaster

mtn again after ive had numerous problems with them seize to disappoint in messing up with peoples money. I called in december to change my debit order from the 1st to the 25th. The consultant said they will change it and it will debit me on the 25th Jan 2016 but i must pay cash to mtn so that my account does not sit in arrears. So i did that. Today on the 3rd January, a debit order of 510 comes off. Meaning i paid twice for december and when i call they say the department is not working yet oddly, they were able to debit my account on a random date. Then the customer rep says they will change it to the 25 as originally requested... Not considering that it will mean that i will be debited twice again.I want my money by monday 4th. Im sick n tired on mtn doing watever they please with peoples money. My family and i are certainly moving away from mtn, this company has no consideration for customer experience.