Regarding Experience Letter

Sir, I was working for a company and served for at least 1.5 years. Afterwards I got a new job during unlock period after lockdown with a good hike in salary. Therefore, in this regard I resigned from the previous company and company has provided my the 1 month of notice period. Relief in the notice period was in the hand of my senior personal and I requested him to relief me from my notice period. He, accepted my request and gave relaxation to my notice period. But unfortunately HR of the company is not listening to me and likes to bound me for few more days in the relaxed period also. As I have urgent joining to my second job therefore 'HR' didn't listen to my request. In the mail itself he, HR, even said to submit the no dues form on or before 30th November but as I have to pack the luggage on 28 and send it to the other city, also I am married and I have my wife with me, for this I have to leave to Dhanbad on 28th from Jamshedpur at 2PM otherwise there will be night curfew at 9 PM. I just booked a cab and asked him to do the help. But HR was not listening to any of my request and asking me to complete it only on 28th. In the email itself, he provided it was clearly mention to submit the no dues on or before 30th and I asked him the question 27th novemeber 2020 comes after or before 30th November. But he was not listening to me. Even I said him to please deduct money my from my balance money as you have provided half during the entire period of lockdown and please relieve me and provide me the relieving letter but he didn't listened to my words. So, I moved forward without listening to him as I have to look into my future. Does there can be any other option through which I can get the experience certificate from my previous company.