Well a super temporary fix is to use landscape mode. Where did you get the parts from? If it was here, ifixit has an AMAZING warranty program
Here's the email for support. That's usual the best bet
http://help.ifixit.com/article/136-email-support
Though their phone support has recently gotten better
http://help.ifixit.com/article/135-contact-hours
After that, if you haven't purchased from ifixit, I would contact whomever you've purchased it from, and see if you can't get a replacement