Poor customer service and culture of passing the buck!

Supersonic has been charging me for a router that I paid for up front and debited my account to recover a disputed debt without my authorization: When I signed up for the in July 2019, I requested a month to month package and opted to pay for my router up front. At the end of the month when my bill came, I discovered that I was charged an installment for the router. My information was captured incorrectly, including the package, the debit date and address. I contacted Supersonic to correct this issue and to pay for the router. The ISP kept charging me for the router and I complained a number of time (five times) via their WhatsApp and email facilities, sending them proof of payment each time. I decided to terminate the service at the end of June 2020. They claim that I have an outstanding amount on my account, but they cannot tell me the origin of the amount. This amount stems from the router installments that I have been complaining about. They do not acknowledge my complaint and never resolved the issue. They then decided to debited my account without my permission, which I reversed. I am escalating this issue.