Bad service and *****s

I had Supersonic internet provider for 2 years. But their service deteriorated and I canceled them by email. They did call me the following week to persuade me to stay with them but I asked them to cancel my subscription. I never heard from them again and they did not deduct any further money. No one told me to return the router. Not even when they canceled it over the phone. To my surprise, I got a deduction of R 2499.99. No one has contacted me to say they want the routers back. just an amount deducted. I checked my email to see if there was any correspondence but nothing. The email went to spam and I tried to contact them to tell them what happened, but after many emails and calls, No one got back to me. Can you help expose them because I think if someone had contacted me by phone I would have known what was going on.