Activation centre

I have recently had to upgrade my wifi with MTN. They couriered my new sim card to me. Then went my debit order went off the charge was double then what is was suppose to be. I have phoned and send emails. My wifi doesn't work. I finally got an email yesterday saying i must phone the activation center. I have been phoning since yesterday. No one even bothers to answer the call. How is this service and how can you charge me for something that i cant even use or get activated. Appalling service!!!!