POOR administration !!!

I have sold my Vehicle in October 2025. I emailed the necessary people cancellation@mixtelematics and I copied in debtors@mixtelematics on the 22nd of September 2025 to give notice and cancel my BEAME. I have canceled my debit order but still get reminders and statement to pay. Its now 2 June 2026 I was debited again. I have emailed every month since and tried phoning but only get music played. the longest I waited on a call was over 10 min. I refuse to phone anymore. PLEASE URGENTLY CONTACT ME!! ACC 21003 . Only call that was answered today was debtors but she puts me through to cancellations but nobody answers, Customer service no answer!