K7 Rave Power Problem

I usually keep the phone off as it is for emergencies only. If I go to turn it on and the battery is dead, I usually assume that it got turned on by accident. Well this happened twice recently and I know it wasn't turned on. Then after recharging, I noticed that it wasn't turning off normally. Where my wife's phone turns off, the icons for the battery power lingers for an extra 10 seconds on mine before the screen goes blank. Apparently it is not turning off, because if I check it later, the battery is half gone and it is fully dead by the end of the day. I swapped batteries with my wife so I know it is defintely the phone. I bought it for $40 in January so I think it is out of warranty. Should I bother to get it fixed?

G