Telkom billing me without service Fault/ blocked

My line got switched with another users line is what Telkom says. So I am unable to use it. When I complained and said that I will not pay for a service I am not receiving, they blocked my line and so I ain't receiving any internet as well. The challenge is I keep getting billed even without the service. They have charged me for this month again after I paid 1000 rands for the previous months. Now they expect me to pay another 1000 rands before they fix my line. Please help