12 hours doesn't seem like that bad a battery life. What did you used to get?
Re not getting emails, how much free memory do you have? Check your Options / Status / File Free. If it's less than 12 000 000 bytes, you need to perform the Memory Optimization Procedure that's linked in my sig.
I used to get something like 80 hours? It's a data only phone.
Anyway, I went to get the phone checked. Battery's burnt out and needs to be replaced and I wasn't getting the emails because something was wrong with my SIM. So I need to get that replaced as well.