My thoughts.....take them as you will....
1. 3 hours to record? Big deal.....it's obvious your heart is not in it which means yout should not have agreed to the project in the first place.
2. The guitarist can record your parts better than you? Really? If that is the case, perhaps you should spend less time asking the Internet their opinion and more time practicing. I'm not trying to offend, just being real. Find me a guitar player that could play my parts better than me and you wouldnt see my studio door open until I emerged victorious. Maybe it's a matter of pride, but perhaps you have put the cart before the horse.
3. Money back? No way. You broke an agreement and left your band mates high and dry. You should be writing them an apology letter if anything. After that, consider how you spend your money and uphold your commitments. .....seems like it could use some work.
Again, not trying to offend, just giving an honest opinion.