Sugar Mobile App - Stability

Hi there, we are slowly going live with a new customer: Southfuels who sell fuel to farmers across NZ. There is a slight challenge with the mobile app. Its not stable, particularly the change between online and offline which is catching Southfuels users out when they are trying to get deals done with farmers in the field..(often offline)
sometimes the app crashes, sometimes it needs to be reloaded etc
its not building confidence with the users..
is there anyone that could assist?