I'm really in need of some help here guys (and gals?)

Activation day 1st Feb. Came home Pipex not working, good. Sky not working, bad! All of the green lights come on on the router, and the modem is syncing at 8Mb or so, but no PPPoA connection. Error 300.

1. Tech support do some tests, and tell me the line is ok. They will send a new router. 3-5 days! Not impressed at all. Should be next day in this situation.

2. Tried removing wireless card. No joy.

3. Tried hacking the login and pw as described here somewhere. OK. Put these into my other 2 routers. No joy.

3. Phone Sky on working day 5. They forgot to order it! Can you actually believe this? The guy cited crass incompetence, and was very appologetic, but that's it. So I'll get the new router tomorrow by courier in the circumstances, right? Wrong, 3-5 days. I'm really p***ed now.

4. My neighbour coincidentally ordered Sky BB. (Not on my recommendation she didn't!) I borrow her new router that she doesn't need yet. Same symptoms.

QUESTION: Are routers interchangeable or will hers not work on my line anyway. It has a different MAC code, so is this used to identify my particular router? The techie at Sky insisted that it wouldn't work. But then she ruined any last semblance of credibility by suggesting that it wouldn't work without the cd software installed, and that I should report the line fault myself to BT.

QUESTION: Do you think it is likely that the problem is the router, especially when I can sync the modem, or could it be a BT connection fault. Friend of mine had identical problems to me. She took her modem to her sisters and claims it worked fine. Her problem was a faulty jumper in the exchange and it's now sorted.

I just don't want to hang around till next week only to find that the router is fine and it is a line fault. 3-5 days??? Noooooooooooooo...

FINAL QUESTION: If it is the router, why didn't hacking work? It's a correctly formatted login and pw. I can verify the login as my mac code@sky etc, but the pw may be corrupt I guess. Doesn't seem likely to me though.

Any help really appreciated. As you can imagine, getting quite desperate now.