Rain worst ever

WORST INTERNET SERVICE EVER. I WOULD NEVER RECOMMEND RAIN TO ANYONE

I need assistance. I have cancelled my subsctiption in December. This is a month-month contract. I have emailed numerous times, phone calls to the customer care line, just with no luck. No feedback nothing. And then you deduct on Friday 4 months subscription money from my bank account, after I have cancelled this. I haven't used this sim in the past 4 months. How can you just deduct money? I need an cancellation letter asap.