I think Ive lost my son for good.

I haven´t lived with my son´s father since he was a toodler. I suffered abuse of all kinds whilst I did live with him as he was an alcoholic and had mental health problems. My son´s father made no contact with him at all, after trying to encourage his father to vist him I also gave up on that after a series of incidents that left my son worse than before he´d seen his father. At the age of seven I was given sole custody for my son. Visiting rights were also established for his father but were never taken advantage of. I put my son through school and university and now he´s living abroad. A few months ago my son told me he wanted to now make contact with his father and needed me to help him. I was completely shocked he´d ask me to do this and whilst I agreed that looking for his father was fine by me if that was now his wish I couldn´t be expecteded to track him down for him. This is where the trouble all started. First there was silence, no or very little contact or replies to my mails. Now, I have had abusive letters from my son saying I´ve deliberatly kept him away from his father all those years, insults  and very cruel and hurtful comments calling me selfish and egocentric. This week my son has said he wants no more to do with me. I don´t know if he´s made contact with his father or not. I am shattered  now and need help with all this.