Rain took my money

I have been using rain for a while and tried not to skip payments eventually the service started lacking so I decided to change provider, since it was a pay per usage I decided to stop paying knowing well the sim will be offline, they continued billing my for 3 months and one day debited 1200r I called and asked them why they took the money since the sim was offline and hadn't been active, they said it was still active and they would not pay me back