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.
Best Answer
Sounds like you may be blocked on her phone.
If you turn your "Show caller ID" to off and try ringing that will tell you. If the call goes through, your number must be blocked(and can be unblocked from her iPhone) or if the call still fails, you may have a bigger issue.