VERY unhappy with installation

I ordered service from Comcast to replace our existing Internet and phone provider. I ordered three phone lines: Two voice, and one dedicated fax. 

The installer said he couldn't wire the fax because it was sitting on a counter with shelves beneath it, and if we were to move it, they could come out and install it. 

I just called to schedule the install, and now I'm told that they "don't do internal wiring," and that we'd have to hire someone to do it or do it ourselves! What in the world??

Although I asked to speak with a manager who could tell me how Comcast will help us out with this, considering I was not told this when I ordered service, I was told "there is no one else," and that it's "Comcast policy."

I'm totally unsatisfied with Comcast. Do I have any options other than to cancel our contract, considering we have a 30-day money-back guarantee?