| | Re: BB9900 keeps turning off
Weird. While reading, I was thinking the aftermarket charger damaged the device. But then you say it stays on while the phone is in use, but then shuts off when the phone is turned off. That isn't consistent with a bad battery, and I don't think it is consistent with a power problem in general, but that latter I'm not sure of.
I agree with Dub, just generally, I would stay away from other chargers, other than OEM, unless it is something in the Built For BlackBerry program. That said, maybe the problem happening when you used the charger is coincidental. It sounds like it may be, to me.
I would try a security wipe. Select the option to delete user-installed apps. See what happens. If that doesn't fix it, do a clean reinstall of the OS, and then test. In both cases, test before you do anything else, before you restore data, before you restore apps, first thing.