N ‘Endless mode’ in Plants vs Zombies 2

A user is never obligated to report bugs, but doing so should always be highly encouraged. Developers can't fix what they don't know is broken. :)

That being said, the best thing to do if you're having problems is to start here: Plants vs. Zombies 2 Support

You'll see a bullet titled "Basic Troubleshooting for iOS Games" that you can click for some really basic advice on how to get your game working. It is worth noting that if you intend to report a bug, you should include as much information as possible, and the most important information is how the bug occurred and whether or not it is repeatable. You should consider following their instructions and then attempting to reproduce the bug before clicking the Contact Us link provided.

Even if you don't have the time or capability to do such in-depth bug testing before submitting your information, it is still worth it to tell them what you know as it has the potential to improve the game for everyone (i.e. reward = knowing that you may have improved the lives of millions of fellow gamers).

Yes, the ones you purchase are separate from the ones you earn in the game. Its possible to have 2 max slots, 50 more sun at the start, 5 plant food, etc, if you purchase the upgrade as well as unlock the in game version.