Thanks guys for all the feedback, much appreciated!
My traceroutes had me believing that there was an issue on Cybersmart's core network, but the call centre checked with the techies, no fault on their network. Next I called Telkom DSL support, operator was very helpful, ran a couple of tests on the line, said the SNR(signal to noise ratio) is off the chart on the wrong side, and escalated the fault to NOC, they fixed the issue in 30 minutes flat. Believe me, I was very surprised, I was expecting a 2 weeks turnaround! Before the fix our latency hovered around 200ms for local, now it's very stable at 30ms for local!
For once I've actually got to commend Telkom on their excellent service!