Supersonic not super

All was well until I was forced to cancel my subscription as I was relocating to an area where there was no coverage. I gave a month's notice for July 2022, sending an email and telephonically. In August my subscription went off my bank account. After a frustrating few days of emailing and phoning with no response, I finally managed to talk to someone who assured me that there would be a refund within one day and that the cancellation was done. This morning I received an invoice for September. No Supersonic owe me two months of repayments and I'm frantic.