Account Cancelled- Still Debit Orders For Internet I don’t use

I have a billing enquiry with Webafrica and have been awaiting an agent to assist me on WhatsApp for 3 days now. My service with webafrica was cancelled in May, yet webafrica still debits my account on the 1st. I have returned their router as requested. I have also tried to send emails and be patient awaiting assistance but no consultation seems to want to help me