Very similar to me. Was meant to be installed on 6th. Now 2 dates, 20th and 26th. Calling customer support proves fruitless. Apparently there's some random date in the middle of the 22 day period with no Internet, that they will lay the cables. But apparently there's no guarantee that this will actually happen. I think these 2 dates are just plucked out of the air to give them time to try and figure something out.
Reports on here state that in majority of cases these dates don't actually result in a broadband connection. I'm with virgin mobile so I managed to get unlimited data on my phone contract for 7 days at a time, but that wasn't offered. And almost not accepted.
I would try and get a dongle. That's what I should have done initially. Let me know if you get any joy