Full and Final payment

Myself Biswajit Ghorai, i had resigned from my previous organization on 31.12.2021 and served proper notice period of 30 days, during my resignation i have informed them that i will be not available in the city for around 6 month as beacuse i am moving to a different city for my personal reason, so that time they didnt provide me the PDC for final payment as they have promised they will provide. But after waiting for 45days now they are saying i need to visit their office to get the cheque they will not provide it online neither they will give to my family member due to their official policies, which doesnt exist actually. Because at the time of resignation as well as joining , no such rules were mentioned in written related to F& F. So in reference to the terms and condition mentioned in the joining letter there was no mention of physical presence to get the cheque. After requesting several times and mail , phone communication still they are denying to give me my last salary. I have informed them that my family member will receive the cheque on behalf of me with the copies of my original documents and i will give the acceptance mail in their official id for their documentation, but still they are not wishing to give the salary. Now I dont know what to do ? is their any law to support their claim, bcz they dont have anything in written all they are saying is completely their overnight made policies.