Tablet is coming unglued

Last weekend I started to take by Dell Venue 8 pro tablet (2013 version) out of its case when I noticed the bottom edge (no buttons) of the tablet was bowed up and was separated from the back of the tablet. I press the edges back together. The tablet worked fine but 15 minutes later I checked and the bottom edge had again separated from the back. After taking the tablet out of the case I could see string of the glue that was holding the top and back of the table together. I tried to completely separate the two halves of the tablet but the edge with the buttons want break loose.

My question is how to put the tablet back together so it will not separate on it on?