Poor Service and Bad attitude

They deducted a transaction from my Bank account twice.I refered the matter to the manager who assured me that it would be resolved asap.After more than two weeks he has still not been able to resolve it.After questioning him when does he thinks that what a reasonable time should be, to resolve a problem like this.He blames their IT for taking so long.They have all the proof that payment was deducted twice and they still cannot or don't want to rectify the issue.