App quits unexpectedly

I bought the mtrip app for my Barcelona & Madrid trip and it was great. So it was a no brainier when going to Paris. Right??!! Wrong.
I was unable to use this app at all. It didnt work at all. the software is very unstable. It hangs up and becomes unusable. Even a software reset didnt work. Turning the phone on/off didnt work neither. Great app if it would have worked. Waste of money. :(

Granny_apple about Paris Travel Guide (with Offline Maps) - mTrip, v1.5.5