Impossible to cancel, be careful

I have been trying to cancel Netstar GO for the past three months since I have never used it. The first time I was told that I will receive a cancellation SMS within a month an I didn't and they're still deducting money on my account. I tried again cancelling several times, until last time I got one of their managers who promised that the cancellation will be effective within 4 hours. But Until today I have received no SMS. The biggest **** is that their debit order is combined with the car track, stopping it will stop everything at once. I think at the end of my contract I will also leave Netstar Tracker and move somewhere else.