Messages will not delete.
I have a 16GB iPhone 5s. My software is up to date. My iMessage glitches and goes blank whenever I try and delete messages, and then will not delete them at all. I now have 1.5 GB of messages. I have tried to delete messages individually, but I get the same result and it doesn't delete. The screen just turns white with the time bar at the top, then goes to a new message, and all of my message strings are gone until I power down and turn my phone back on.
iPhone 5s, iOS 8.4