Impulse IS the way to get it downloaded.
I'm not sure you can get a refund if you cannot configure your PC to download. Many people (myself) included have downloaded it. And since you can download it multiple times (no limit like some games), then the only reason you cannot have the game is due to
1) You having no internet connection
2) No space to put it on your machine
3) No ability to connect to Impulse due to an issue with your setup
4) An issue with Impulse itself
Of these, the last is probably least likely as they have had a while to get it ironed out. Note that if you are running Vista you need to run as an admin to do the install...
Note that Impulse is self patching, so the version you download may want to update itself before you can use it...
You will also need to specify a proxy server to use if you are not using a normal gateway connection...
