He was maybe apprehensive on the phone because he was clear few months ago that he wants neither romance nor friendship with you so he was probably unsure why you are calling. But he was still polite in his responses, which is nice of him. It’s ok that you called and ok that he answered and was courteous. I’d not push any further. If you feel tempted to check up on him and his activities on Facebook, I’d try not to if possible especially if it forces you to ruminate about him, keep moving on instead