One of my contacts (my girlfriend, unfortunately) can not complete calls to me. When she attempts to call me, I never receive a call, and on her end it never rings (and I think it just ends without going to voicemail). I can still call her, and we can both still text each other. This does not happen with anyone else.
I have checked whether she was blocked (it does not appear so). I deleted her contact info and recreated the contact. I also reset my network preferences. Nothing has worked. It is very annoying -- please help!
Note: I have an iPhone 4 and she has an Android.
She should call her tech support and report her call is not going thru to you. Since none of your other contacts is reporting this problem and you can call her, the problem is most likely on her end and her call is not being connected.