Third Party App - i-Boating:Nautical Marine Charts & GPS worked well originally, but now crashes when started. No response from the developer - Bist LLC.

Old iPad Air with cellular. Software version 12.5.7. Purchased the i-Boating : Nautical Charts & GPS with USA/Canada charts and the app worked fine in May of 2025. I don't have version history and I may have updated the app if the Apple App store provided an update. App store still says the app will work with this iPad.

Earlier, I did get an error message to the effect the key used to unlock the in-app purchase of the marine charts "is invalid or is in use on a different device". But I did not "share" my key, nor did I install the app on a different device.

Now the app crashes on start up. The iPad shows the app is running but it doesn't display, you can force the app to quit by swiping up, but the behavior repeats when you restart the app (I don't know how to attach the video).

I tried to contact the app developer, Bist LLC, multiple times using the email address provided by the developer. No reply after after several weeks. I would prefer to continue to use the app - it's a useful and inexpensive chart plotter solution for those of use with small portable boats.

Failing getting the app to work, I have asked for a refund. But there had been no response from Apple. Am I wrong to think Apple has some responsibility for the apps available in the app store?

Hoping for any help, - but I did all of the recommended steps, restarting the iPad, removing the app, re-downloading the app, reinstalling the app, reaching out to the developer, seeking assistance at my local Apple store - none changed the app's behavior.

Thanks in advance,

Glenn