TCS not releasing me early

Hi, I was working in TCS since last seven years. However, I had switched job now for better prospects. The new company said that they are not willing to wait for full 90 days notice period. They can wait for 30 days max as it is an urgent hiring. I put in my resignation mentioning my last working day and followed up for the one month noticd period Inwas working. However, TCS is saying that I have to complete the notice period. In their separation policy, it is clearly mentioned that an employee can ply in lieu thereof for the shortfall in notice period which I am willing to pay. The HR is saying that to release early is at business discretion and right now they are not ready to release me early. I have left the company now and they have sent me email for absconding. They are saying that as you have left unilaterally and the decision was not bilateral, it is considered as absconding even though I was communicating regularly via email during the one month I served. They are saying that they will not release my relieving letter and Service certificate. Can they do that? Can they block my PF or Gratuity? Also, what is the action they can take? I read on this forum that according to Indian Labor law, company can't force an employee to complete the notice period. Can they file a criminal case against me? Or this is a matter for arbitration? Just to add, I have not signed any kind of bond or contract with them. The only asset I have from company is the laptop I had received as part of work from home order due to covid 19. I have repeatedly asked them to tell me the procedure to submit the laptop back. Regards