Q10 with 10.2 -- significant problems since updating

Hello,

My phone upgraded to OS 10.2 2 weeks ago, and it has been very problematic since then.  As a high level summary:

xx the battery drains like crazy.  I have tried any number of solutions found on various message boards to limit the battery drain, but it just doesn't work.  The device monitor indicates that "standby" eats up most of the battery life.

xx the phone freezes and hiccups all of the time.  Few videos play seamlessly without frequent pauses.  Also, sometimes the phone doesn't ring when people call -- the phone must be in a freeze during the call, because it will go right to voicemail, and I didn't even have an opportunity to pick it up.

xx The text messaging feature frequently stops working.  I can see received texts in my Hub listing, but I can't actually open the text conversation.  It acts like it's opening it, but then stays on the Hub listing.  Also, sometimes I can open the text conversation, but replying won't work.  The mail icon (for sending) stays darkened even when I've typed text.  In all of these instances, the only way to get things working is to reset the phone.

xx I get no notifications when there are voicemails waiting for me.  I have to proactively check voicemail to see if there are messages (which, combined with the phone-not-ringing issue, creates problems).

I connected with someone at AT&T via chat, and they basically set to wipe the phone or contact the provider.  Blackberry says to contact the carrier.

I just want to know if there is a way to make this phone work properly.  I was very excited to get a Blackberry because of the keyboard.  I am willing to forgo all of the many apps and bells and whistles that are available for other phones because it is more powerful for email and other business uses.  However, if the functionality of the essential, nuts-and-bolts features of the device don't work properly, I can't see how it is practical to keep this phone.

Has anyone had a similar experience, and can anyone help me make this phone work the way a phone in the year 2014 should work?

Thanks,

David