BEING BILLED MONTHLY FOR 5MONTHS AFTER CANCELLATION REQUEST

Have 2 fibre lines at different locations. Asked to cancel 1 of the lines more than once. The first date I sent the email to cancel was 14February and I have been receiving invoices monthly since!!! Even emailed their complaints email addresses but still happening. No-one lives at the address they are billing me for...! I thereafter asked to cancel the other fibre line as was so frustrated but guess what... Same problem... No response. TERRIBLE SERVICE AND WORSE COMMUNICATION SKILLS! Please sort this out.