Don't even know what this is for

There is an amount of R57 that goes through my bank account every month. I have stopped this debit order at the bank but Fonesure still puts it through. I don't know where to contact these people. This month it also went through although there was no money in the bank so now I have to pay R125 bank charges for the amount that did not go through. This is giving me a bad name at my bank! Please stop this debit order as it is not something we have asked for. It is really annoying now