Lost sms msgs in manilla2d

I am new to manilla2d and I have had a problem with it freezing up after several hours of inactivity. When I restart, any new sms msgs that I have received but not yet read, disappear. Is there anything I can do about this, I also have been trying to change the theme using M2D Customiser, but I never can get them to show up on the theme manager. Any help would be greatly appreciated, thank you.