Motorola Droid X :: No Ring / No Missed Call Indicator

my Droid X is doing something completely unacceptable.It misses calls.There's no ring, no missed call indicator, just suddenly a voicemail indicator pops up to tell me that someone left a voice message.Sometimes it only happens once, and will receive the next call without a problem.Sometimes it'll do it three or four calls in a row.I've already talked to Verizon about it, and they've gone through the script. Before I call to yell at them until they replace the phone with one that works, I'm wondering if anyone else has any experience with the problem.