REFUSING WITH MY REFUND

I'm currently paying a home with FNB, I recently changed the bank which I receive salary into, so I have been unsuccessful in switching the debit order into my new bank. So, I decided to pay it manually by transferring some funds into the home loan account. The 24th I paid the loan by transferring funds. On Monday the 2nd they deduct (original debit order date is the 25th). Now, I want a refund, they giving me run around, filled forms, application rejected with no reason.

Fnb is a very bad company, can't believe I was considering switching banks to them, disapointed big time... Actually very angry