Plus (+) sign in the incoming calls

I have a Samsung Note 3 brought over to AT&T from Verizon. Everything has been working fine, except all the incoming calls have + sign added to the number, so I cannot return call directly from the call history. When I made call from the history, I would receive message that my call is not completed at dial, etc. How can I get rid of the + sign? I have searched on line and it seems few people got the same problem, but no solution yet.