My ADSL disconnects a couple of times per day... The internet light on the router just goes red and then I need to turn the router off and back on again in order to get it working again. I can't even connect via Network Connections from the pc itself when in that state.

Is this due to Telkom, the router, ISP or is that just what ADSL lines do in general?

In Nelspruit, I used to have a Billion 800G router and never had this problem. However, that router was assassinated by lightning and I've had the problem ever since. Since then, I've used a Netgear router, some other Telkom brand and currently using a Billion 400. I've also moved to Centurion since then so my initial thoughts that the line got somehow damaged by the lightning also seems to be invalid since the problem persists here.

My router is set to connect automatically to my OpenWeb uncapped account, but I do have some capped ISP accounts set up in my Network Connections that I can use from time to time.