What should I do now?

My 21 years old son who is living abroad , he without my wish has got married with the girl who hates me and has abused me several times. My son loved me a lot when he was at the home . But after meeting with the girl in the other country he has changed a lot. His wife doesn't want him to talk to me and doesn't allow him to call me . She has also restricted him from talking to her sisters or any other family member and she wants him to forget his past i.e his family.He obeys him and requests me not to call him and disturb him but I can't help it. Sometimes he talks to me in a very nice way and sometimes he shouts at me. I can understand it is his life but why can't he give me 2 minutes from his 24 hours and talk to me nicely. Don't advice me to forget him as I can't. I keep on calling him everyday and he talks to me very rudely.What should I do?