Employment

My company has official 90 days notice period. I opted for notice period buyout. But after they sent me the buyout amount details I am not able to afford it. I told them i am unable to pay it so I am thinking about serving full notice. But no response from company. Now my relieving letter is on hold by company . I got a job offer from the company who is the client company of my previous company. One other thing to say that I was on bench and I initially I told them that I am serving notice till month end but company released me early and asking for money for notice period buyout. I had to join the client company because without relieving letter no company is willing to hire me please help me what I can do.