Previous employer blacklist me

Dear Sir, I was working in a company , noida . Due to parents health I resigned from the company. Now , I am unable to join the new employer , as everything goes well with the new employer till I don't give them reference of my. Previous employer. After that , the new employee even stops picking up my phone. I talked to my previous employer , HR told that they have blacklisted me. I am too mentally harassed , pls advice. What can I do.