Cancelled subscription but Rain still billing from my account

I cancelled my rain subscription in February due to poor area in the area I had currently relocated to and the cancellation was confirmed by the service provider. On cancellation they highlighted that the last debit would go in March month end although I will not be connected for that month, which did not make sense to me since services is on a monthly basis and I pay for what I use for that particular month but for that month I received no internet and yet I am getting billed. Nonetheless, the payment did go through but again month end of April another payment went off my account and I have been enquiring about it and I am told the payment that went off in April was for March, what about the payment that went off in March? According to the agreement and it is also on their website they highlight that upfront payment method is used and it covers for that particular month, so why was I billed for month of March and April when I cancelled my agreement in February? I want my full refund.