HR not providing relieving documents

I had sent the resignation mail on 7th Jan'21. I had reported to work even after my resignation. It was only the last 5 days of January where I haven't reported since there was no clarity regarding the resignation acceptance (Initially HR said to work for Jan month, later on he said to work for 90 days). The pay of January month is not yet credited to my account. The next update received from you was to submit the laptop on 15th Feb'21. The same was done by me. Even after the submission of laptop, there was no update about relieving letter or my last working date. Though I had asked the substitute for unable to serve the notice or to reduce the notice period previously itself, I was said that the company policy was only to serve the notice period of 90 days. On March 1st I received a mail that I need to pay 3 months of salary and my last working date will be Dec 31. I refused initially as the HR wasted my 2 months and I didn't had that amount. Now in Aug I am ready to make payment and obtain the relieving documents, HR is not responding. Please suggest further