Hi @tacp, let me see if I can help out here!
Based on your post I am guessing that the bottom part of the touchscreen is not responding on your phone, am I right? Have you been able to carry out a quick test of the touchscreen in order to see if the screen works as intended? To do this, find and tap Settings > About phone > Diagnostics > Tests > Touchscreen.
Another thing that you can try if the bottom part of the touchscreen is not responding is to try to perform a software repair using a computer and Xperia Companion. Please note though that a software repair will erase all user data, so remember to do a backup of your user data first.
If the test of the touchscreen fails and the software repair fails to improve the functionality of the touch screen I suggest that you get in contact with your local support team in order to have your phone sent to a service center to be examined and repaired. If you have any questions regarding the service, such as routines, warranty and consumer laws, these type of questions are best answered by your local support team as well, as they vary between markets.
Try this and let me know how it goes! And please return if i have misinterpreted your question in any way!
