Customer service

Metrofibre debited a crazy amount on my account after paying for fibre, no missed payment. I tried to call support and no one is answering. I called 8 times, the one time someone answers before I could say hello, they said my line was bad. I tried WhatsApp, I keep getting the same automated message, no help. They are saying my account is suspended due to an outdated amount when I’ve never missed payment. I want my money back. I even tried to calculate how they came up with that amount.