I can't play with Friends on steam

[Struten]

So this problem is kinda annoying, i have two friends who bought the game on steam and i bought it on disc and now it seems like we can't play together. well sortoff at least, they can join my servers but i cant join theirs, the thing is that they can't play on my server for that long because i have bad internet connection and they get over 9000ms/ping. now when i try to join their servers I type in their servername but nothing pops up. please help!

[DukaSoft]

did you install the latest patch 1.2?

[Struten]

did you install the latest patch 1.2?

yes

[Heizer]

Did you make sure you are looking on the same matchmaking server they hosted on? Also check your filters options.