Supersonic incorrectly billing customers after cancellation

Seem to be echoing what many have already stated.. Cancelled subscription in 2020..30the November. Still paid December as part of 30 day notice. Got the mail, got the screenshots from the whatsapp pricess.. November 2023. Receive notice of pending legal action for January 2021. Well after the 30 day period.. Sent Queries in, all, available channels they claim to use. No, response at all. Customer service just say they have escalated.. Have multiple ticket numbers.