Sony ericsson k850i blank screen problem while talking

I have my Sony Ericsson K850i and I love this but sometimes it gives me problem. While on talking screen goes blank and keyboard light is on, I can lock it and looks like phones is one. It vibrate also...

Also sometimes when I am texting, it suddenly goes blank and nothing there. I asked my friends about this and he said that one of his friend also have same phone and he is also facing it.

I think I should now ditch this phone.

May be you should try to disable power saver mode (if there is any).