AT&T Tilt battery issues

So yeah, I have an AT&T Tilt, but the battery dies in like...seven hours. I charge it at night, but whenever I use it (Internet and music, mostly), the battery dies almost instantly. Hell, when I checked it this morning after unplugging it for about half an hour, the battery was at 71%.
I got it for Christmas last year, so I'm assuming my parents bought it in late November/early December, and I don't think a phone like the Tilt would die that quickly.

Help? D:

 

This is happening to my mom's LG Chocolate, although she's had it for a while. Whatever you do, don't buy a new battery and put it into your phone. It won't work. D:

 

this happened to my old sidekick
you actually damage the battery whenever you use the phone while its on the charger
unless your actual phone is damaged then all you have to do is buy a new battery

 

No, the thing is, I don't use it when I'm asleep. D:

So I'm really at a loss of what to do, since I've heard that using it on the charger kills it (happened with my last phone) and I didn't do that this time.

 

Uh...I don't. It's wireless, and I can only get a connection where there's a router. Which is at my house, pretty much.

And I know that it uses more battery when I listen to music, but I don't think it should be dying when I'm looking at pictures already on my phone or playing solitare.
It's not like this is my first phone; I know what should and shouldn't kill batteries. <_>;;

 

it could be a faulty battery, I would contact your cell company and explain to them what exactly is happening, there COULD be a warranty on the battery, or they might ask you to send/bring it in, and they will replace/repair it

 

I'm not sure if this works with your phone, but try unplugging and replugging the phone after it says it's full. It works for my phone. (Motorola v180)