Can the company ask for notice pay after terminating him?

I was working in a company for 4 months. They gave me a laptop and a mobile as assets. I told them I will quit next day without serving any notice period as they were constantly changing my shift timings which were not discussed and that was the reason of my quitting. The next day while returning assets I hard reset the phone and deleted internet browser from the laptop without any written permission. The company then accussed me of data theft and breach of contract and said because of resetting and deleting permanent loss of important business data occured. So instead of providing me relieving letter they provided me a letter of termination and in the letter they asked me to pay a certain compensation amount in lieu of notice period otherwise they will drag me court. They threatened to sue me and with forceful pressure took my sign on a letter that states I intentionally deleted confidential and important business data and it is lost now. The data was not completely lost as almost all of it was on backup and also the data wasn't business,confidential as well as important. What should I do now?