Ask for the Look 585 or Cervelo loaner bike...

Seriously though. I'm like you. I'm too nice. So it kills me to see other passive people get trampled on.

Just go back and get your bike and take your biz elsewhere.

For me, the pen is mightier than the sword so afterwards write a well thought out letter to the owner of the bike shop and tell how loyal you have been as a customer, how you feel about the bad customer service and that you will tale yours and your friends business elsewhere. If they are good they'll write or call you back and offer some sort of reperations for jacking you for so long. Or at the very least, apologize.

If they do neither than they are definitely not worth going back to.

You can be forceful but not rude in your letter and still get your point across.

On the other side of the spectrum, if I get very good customer service, I also write to them and let them know.

Good luck!