Upset client

Once again MTN has disappointed me!

I phoned last week to change my banking details on my account. I specifically asked the person if the debit order will go off the new account details and she said YES... Yesterday the account went off my old account and was returned due to no funds (this is why I changed the details) Now I owe the bank a R120 honoring fee and R11. 50 to MTN for insufficient funds!!! I have no work, so I made a loan to pay my MTN account which was credited into the new account... If I knew that they were going to debit off the old account I would have requested the loan be paid in there (this is why I ask which account it would be debited from)

Who is liable for the outstanding funds now? I DON'T have any extra money!