Company are not providing me experience letter

Hello sir, I have worked in a company from the last 3years but in this lockdown company office was closed. But after 2months company office has been opened again. But the owner of company didn't give any salary of these two months. It is not an issue but the owner's of company open the office silently and they are calling the persons according to their needs. They didn't understand our needs. We also faced lots of problems in this lockdown but they didn't help us. I was waiting for their call but they didn't call me to join again. He was continuously ignoring my msgs and calls. So I have send the resignation letter to him. But they didn't give me any response till now. Now I'm requesting them to provide me experience letter so I can join the new join. But the owner's of company are not giving any response. Perhaps they also don't want to give me experience letter. If I visit the company office they will not give me permission to enter in the company. Because same thing was happened with one employee. Now, Plz tell me what are the possible actions by which he can provide me experience letter. If there is any law plz tell me. I live on rent in Delhi. So I am facing lots of problems. But they didn't understand my problems.