I think I've figured it out...

I showed the man at Media Markt a camera phone picture of the wall plug I have for my phone line and he told me that there was nothing I could do but wait on the package from Alice because I needed a "splitter" of some type. Not wanting to give up after getting this far, I went to an Internet Café and did a little research... apparently my apartment has a "BT" type of connection and I need an "RJ-11" jack for my DSL modem. I can buy those for under 5€ shipped from the UK but I want something sooner. I'm going to go back out in a little bit to a different technology store and see if they have the adapter. I think I'm also going to look around Media Markt some too because I don't quite take the Alice man's word that they're entirely unavailable.