let's roll this back a bit.....you were asleep. your phone rings at 2:45 in the morning. it's an unknown number. you ANSWER.
so if your ringer had been on silent, or better yet, phone turned OFF, your sleep would not have been interrupted. if in the future you do not answer UNKNOWN CALLER numbers, your peace and serenity would not be interrupted.
as for NO CONTACT, do not expect him or anyone else to respect your desire to go no contact. that is something YOU promote and support.