Dual Employment

i worked with a company (A) for more than 2 years , I got an better opportunity from some other company(B). I resigned from the Company A but they asked me to serve the notice period , Company B was not ready for me serving the notice period of 90 days. I was ready to pay the buyout amount to Company A but they didnt agree to that also. instaed they allow me to take leaves for 2 months and take the relieveing letter after completing the notice period. I talked to some hr in company B that explained complete scenerio to her, she agreed to that and asked me to join even when I was in leave period . But after joining company B, their RMG team started asking me for the documents which i really didnt have. I write a letter stating that my last working day in company A is 29 May 2014 and will get relieving letter on 29 th july 2014 (which is supposed to be my legal release date) on the company's letter head and submitted that to company B. Company B reached out Company A for verification , and got a negative response. Company B rejected my offer and Company A is taking some legal actions on that. I know it is my mistake but is there any way out to this. As if i can get a clear record from Company A so that I can continue somewhere else in the same profile. Any Advise will be of great help.