How to evict someone whose mother, now deceased on 4-09-2019, we allowed to use a shop on property

We had bought a plot of land with Kuccha structure comprising of two shop rooms in 1982 at Titagarh, West Bengal. This was occupied by two people. They used to give us rent of Rs. 25/- per month. In 1996, i got the plan sanctioned from Titagarh Municipality. I asked the two tenants to vacate the premises which they did and the legal tenancy ended in June, 1996 effectively, when i started construction on my plot. The small house got constructed and we did Griha pravesh on [deleted]. One of those tenants whom we has evicted then requested us to allow us to use as a shop in the new building. She being a widow, i granted her request for the same but free of cost with the verbal committment that she can use it only during her lifetime. Now, she passed away on 4-09-2019. Do her inheritors have any legal status on the shop. I have asked them to remove their wares and disconnected the electricity connection that was provided. But they are moving around the society asking the society members to intervene and allow them to continue in the said shop. i made my position clear i shall not allow you all to continue. kindly vacate when your griefing period of 40 days is over. They are Muslims. They have also tried to get their religious and political leaders involved in the matter citing that they are being targetted as they are minorities. I do not want to use force. How to go about it? Rajesh Singh