If it started after outages it sounds like Telkom have upgraded (Their word not mine) your exchange to use ASSIA.
It tries to dynamically balance your line by adapting to the speed that has the least line errors.
In theory it is good but in practice it has helped some but totally crippled others.
I suggest you contact Telkom and report the situation.
That is what ASSIA is doing now on my line but Telkom Techs are yet to figure out why and what is wrong with the line and where.
I am on 8mbps/1mbps for a 10 Mbps DSL Line at the moment.