Kyocera lingo..5 minute beep..help Every five minutes my phone beeps and i can't find the source

Question

Every five minutes my phone beeps and i can't find the source and it happens for days at a time then stops and comes back in a couple more days.

I'm on my second Kyocera K312, and now IT has started the 5-minute alert thing again as well. I took the original one to a Metro PCS corporate store, and after inspection the simply replaced the phone with the same model. Now, here we go again