phone calls out and in work intermittently as does texts in with black screen on some calls in?

Question

some calls are accompanied by a black screen on my handset saying The process com.android.phone has stopped working  Some days I can call out sometimes I cannot as the phone comes up end call without connecting. People send texts and they dont come sometimes they do from same location. People phone me and dont get a connection and then on another occasion they get through from same location.

Answer 1

What type of phone system?
Who is the provider?
What country(ies) are involved?
Any other details and specifics you can provide will be essential to attempting to assist or guide you.