The Unfixable ADSL issue

I've been on 0.5mbps for the last 2 weeks. Technician has been at my home everyday for the last week and a half, nothing is solving this problem. He'll go to exchange and do whatever they do there, come to my home, plug in his laptop into my line and speeds will be back to 4mbps. Then I would plug it into my PC again and speeds would also be normal at 4mbps. However, the next day when I switch the router on, my intermet is off and I would have to enter my Internet username and password again for some reason... And speeds be crazy slow at 0.4/0.5mbps. After cables, filters and connections were checked and confirmed to be working, the Technician said the problem could then be with the ADSL account myself. I phoned Telkom and explained this to them, but as we all know what is the level of intelligence and s****set we get from the service provided by those call centre agents. They instead send the same Technican out again. They ignore me when I tell them what their own Technician has advised. This one lady claimed they can't recreate my ADSL account as I will be months without internet... Really now???