Registered Agreement is sale

I had purchased apartments in May 2014 from builder by paying 20 lakhs and make registered sale agreement only 50000 was my outstanding which I have to pay at the time of sale deed and possession but unfortunately the construction of the said apartment was stoped till 2017 after that the one of the director absconded when I tryed to get the possession and sale deed the another company director replied that company has not received any amount on these agreement of sale th my registered sale deed was executed by that director who is absconded since 2017 I pay 2 lakhs in company acnt and 18 lakhs in that directors bank account after that I come to know that same flat is already sold to another buyer by changing flat number as A 1/ 105 but actually there is only A ,B, AND C block there is no A1 block exist not even in municipal Plan and no physical A1 block exist but the another director handed over the flat to that buyer who have sale deed of block no A1/105, in my registered agreement of sale it's mention A105 which is as per the plan and physical