Experience certificate issue

HI all, I had joined an IT startup just a few days before covid pandemic and worked for 5 1/2 months. During the pandemic, employer told me you can work only for basic pay(which is 35% of my orignal package) or can go if i have any other opportunity. As i dint even imagine this will happen with me, i had no other chance . so i continued with that salary and after three months they gave me salary with 15% loss of pay. But the fear of losing my job was with me throughout the stay in the company. so i started searching for a better opportunity and got offer letter from an MNC. when i resigned, the resignation was accepted subject to serve notice period of 2 months on mail. But the next day, my employer tried to convince me to stay. But i refused to stay as job security was the issue. Afterwards,i got a call at 8 pm that there is no need for me to join company from the next day. so, when i asked about my service certificate, HR questioned how can you ask service certificate for just 5 months working. on requesting, she told she cannot assure of anything. All my company services were terminated abruptly without any prior intimation. now i need Payslips and service certificate to submit my new employer. Can anyone please help me what can i do in case my old employer refuses to give me my payslips and service certificate