Frustrated with getting a line transferred to owner

I have family that live in Mitchellsplain. They had a tenant who lived on their property who installed internet at their house. He then moved out without paying or cancelling the service. I've been trying for months now to get web africa to cancel the account so they (the actual owners of the property) can take over the connection.

It is becoming extremely frustrating. I've sent in proof of address twice already. Every time its the same back and forth. Please help