MFC triple debts accounts

i asked you guys to debit my account for the arrears and this months installment...and you did...then you tried to debit my account again...my account is up to date. by why debit my account again. there was not enough funds there so theres a return debit fee i must pay. please could u advise why urll did that...and u need to refunds me my return debit fee as its not a issue on my side. this was send to your client care division and it stated 7 to 10 working days to get back to me. there was no apology, just a request for my bank statements ... you guys service stink,,, I wish I could move my finance to another institute as you have no idea on how to deal with client at all.