This is something I'd have to investigate personally for you. Telkom network, restart your modem, and exchange issues are not non-answers. They are pretty much standard phrases in fault-finding and diagnosing, and if you were to chat with me directly I'd in all likelihood use the same register when fault-finding with you.
People assume there is a button we have that is either "fix all" or "break things for this specific customer".
Doesn't exist.
Disparity in results with other ISPs may be for a host of reasons. I've personally posted extensively about this. In fact you asked me the question recently and I answered quite in-depth about it.
http://mybroadband.co.za/vb/showthr...eedback-thread-Part-2?p=13907597#post13907597
Also remember that support staff are first line support - they are not technical engineers. They do go through the basics, because 9/10 the basics are what are required. The rest of the time they escalate queries to more knowledgeable people than them. I assert that our support staff are more competent and knowledgeable than your average support staff member though, and are able to assist in some fairly advanced queries - we also don't queue escalations up if need be - if someone with the skillset to diagnose a fault in more depth is available they will be asked to assist from the get-go, while in a chat between customer and support staff.
BUT, I am confident that considering your previous queries about exchange congestion with me; the fact that our agents are mentioning the exchange to you; and that the issue from what I can tell on the surface is one that is replicated with the same results, that this may in fact be a case of the problem having been diagnosed correctly. Not sure. I don't have the details of your ticket associated with a forum name yet.