Debitting account when they want to

Every month Vodacom debits my wife's account when they see fit. After numerous attemps I finally got the debit order cancelled, They are supposed to have debited our account on the first of every month but that does never happen. The only time that happens is when there is no money in our account. Now once again we were charged for a debit order reversal after the account was paid before the debit order was reversed. Seems like this ia the way Vodacom conducts business so that they can get more money into their pockets. I want my money back from them for the reversed debit order from their side and that money to be advanced on my wifes account. Unfortunately for Vodacom they are losing yet another customer as this contract will never be upgraded ever again. I am going to cancel this contract due to the fact that Vodacom cant stick to their promises and the fact that they do not know when the 1st of the month is as they are only taking the debit order on the 5th of the month. So sorry Vodacom, but you are losing another valued customer as you call it.