My phone Won't hang up!?

[meachi04]

Can someone point me in the right direction. I'm not sure if this has been posted before, but when I hang up on my diamond, it doesn't. I can be in a regular convo, and end the call, either by the button on the phone or the "end" button on the screen and it doesn't hang up right away (it shows that it has on the screen, but I'm still connected). The EndCallTime is also set to 0 (no delay). This also happens when I make a mistake a click someone in my contacts, and I try to hang up and it doesn't, even after it shows the call is hung up. However it does not do this for every call. Any suggestions?!!