Used app for two days and now won't work – Kwit - Quit smoking and vaping Review

I paid for the app after seeing it was helping me get my mind off smoking. Everytime I had a craving I would open the app, put in a craving, read some inspiration quotes, see my progress and get me to not smoke... I decided to pay the full price for full version. But now, one day after getting full version, app won't start. Keeps quitting on open. Tried restarting, closing all other apps, still nothing. Please fix this!
Review by WushuMaro on Kwit - Quit smoking and vaping.