Supersonic cancelation process is the worst! CANCELEL my account

Supersonic is making me run around in circles to cancel my subscription. When I signed up the guy said it is a month to month contract and you can cancel anytime as along as you give 30 days notice. I sent a cancelation email on the 11th of April and nobody got back to me. I called back 2 weeks later because to find out why I haven't received feedback and they said they tried calling me but I kept drop the call, this did NOT happen!!! The lady on the call said the cancelation department will call me back and they still didn't. 4 months later these people are still billing me as I'd I did not cancel my subscription, I would like my subscription calbcelled PLEASE and I do t think it's fair that you guys keep charging me every month and ruining my credit score!!! They have billed me for May, June, July and August even though I have requested a cancelations. Now I must run after supersonic to cancel when I was told it's a month to month contract while they keep charging me and get me in debt? This is unacceptable.