Missing calls in good signal area!

[Redx]

Just recently got the LG Phoenix with AT&T for my work phone. Phone is great, minus a few missed calls.

I live in the St. Louis area so signal is always great, but even with good signal I seem to get missed calls. It will ring for the other person but not for me. And it will go to voicemail. Called tech support and they said just take battery and sim card out for a minute or two.

Any tips or advise?