Shame man that you have to go through those issues. Hopefully you get sorted out soon.
I myself had issues with my line recently. For the past few weeks my line use to drop with no reason where it could not sync at all. Then it comes back up when it feels like. Had telkom come out about a month ago where the guy fixed the line. Got the telkom guy out again on Monday and he told me there was no issues on the line. The weirdest thing that my line sync at 18 then drop to 16 then suddenly to 6 again. It's now on 12 currently on the w8980 on adsl2+. Dunno if it's got to do with telkom busy upgrading the exchange to vdsl. I asked the lady on Monday to bump me up to 20 as she says I can only go up to 20. I want to buy a vdsl router today to test if the line has been converted for vdsl. I am about 150m from the exchange.
Hopefully I find a router today
I have pretty much the same issue as you, line stats would go to **** and line would drop and sync at different speeds and then eventually come right again and be stable for 10 hours or so.
Even now with me being on VDSL and having amazing stats my line still drops. On my 4th router now so most certainly not the router.
I first upgraded my line to 20Mbit ADSL 2+ and then when I got my VDSL router, a call to Telkom 10210 got me put onto VDSL within 5 minutes