My rain unfair deduction.

I had cancelled my sim end of january due to being in an armed ******* and my phone was taken that had the simcard in, i cancelled yet come 1st of march i get sms R479 deducted for february, log a complaint and get told it was usage in february,hiw could that be if i did not use a single megabyte of data for the whole damn february? And the my rain app says next payment 1st april so which means they will take money again for something i cancelled and do not even have anymore. I really thought they were a good company but highly disappointed now.