When my wife upgraded her iPhone she gave me her 5S and I installed my SIM card. After using the phone for about a year every time I tried calling my wife's cell number it goes straight to voice mail and she doesn't receive my text messages.
She can call and text me but I can't call or text her. I checked. The Apple and iCloud emails on my phone are mine. I even tried putting my SIM card back on my original 5C and it still has the same problems.