I've had my Samsung Droid Charge for a little over a month and I've noticed that every couple of days, the ringtones just go silent for some weird reason. I'll get calls and not know it because of this. I'll restart the phone, then it's fine again. Then, about 2 or 3 days later, no sounds again. It's not like I've accidentally turned them off or anything, it just goes silent. ????Anybody else having this issue?