Legal notice to hr

Hi, I had a bond with my employer but work environment was not that good so i had to resign within 2 months of joining. My CEO said pls continue to work and i can leave without a bond with two month notice any time. Again, after 15 months my boss puts an allegation that i am spoiling a team, and nobody is happy with you. So, i hurt and took a decision to resign and put down the papers. Actual drama started post my resignation, as MD/CEO started threatening, begging to continue to work messages together. Since I had committed to join my next organization I didn't heed, but continued to serve my 2 month notice period but in fact I served 2.5 months. But on the salary day, my HR sends a pre-written mail and forced to sign if I want to receive the salary for the month. Since, I had served more than 2 months notice I stopped working from that day. I sent a request mail twice, but they ignored my mails. Finally, I sent a legal notice to HR manager, but it was received saying "ADDRESSE LEFT WITHOUT INSTRUCTIONS". The next day I served notice thru WhatsApp and mail to my reporting manager, CEO, HR and CMD and all. Now, HR manager who was left without instruction has blocked me in the whatsApp. How to go about it..