Web Africa doesn't confirm cancellation of subscription.

After having a very bad experience with poor LTE connectivity, I have at last managed to get fibre. I have contacted Web Africa 3 times to cancel my LTE connection and have received auto responses saying they will get back to me within 48 hours. But they haven't. I've been to my bank and told them that no further payments should be made to them. I contacted Web Africa again and told them that I would regard any further attempted withdrawals from my account as *****. Wouldn't you guess - an auto response that they would get back to me, which they haven't.