Worthington has confirmed his frustration that McCartney sent a text message to confirm his retirement.
“The situation is straightforward,” Northern Ireland’s manager said.
“George McCartney sent a text message to one of my coaching staff to say he no longer wished to play international football.
“At some stage someone must have had a word with him to say it might be a good idea to speak to me, so I got a call from him on Monday morning.
“That was the end of it. He has tried to contact me a few times since but I have not accepted the calls because he doesn’t want to play for his country.
“That is his decision and as far as I am concerned the matter is closed.”
