Debit almost daily

Got the uncapped 10 mb prepaid from rain. I got it for a week and canceled as I pay for a 10mb but only get 2 to 3 mb on the good days useless according to me. I have paid the prorata to activate the sim and within 1 week I canceled as there is no use paying for something that's not worth it. Now they debit my account almost on a daily basis and it's going on for the second month now. How can they try to take money if I have canceled and it's no contract only prepaid. I think they are quite *****