Landlord falsely claiming rent

Hi we are running a family business for the past 50 years ,It was started by my grandfather and after him my father is running the business ,The shop is located in prime location and it is pagdi system shop, The original owner of the shop has demised 30 years ago and she is sole owner of the shop she has no children ,but after her demise a lady claimed she is grand daughter of the landlord and landlord transferred the property to her and claimed she is new owner of the property and claiming rent for the said property for the last 30 years,but when we recently enquired about the property we came to know the property hasn't transferred from original owner to this lady and also she is not grand daughter of the landlord she is distant relative of the landlord so she falsely claiming rent all these years,we are paying rent to her and also paying property taxes all these years,Is it possible for us to sue her for falsely claiming rent for the past 30 years and claim refund with interest and also should I stop paying rent in the future ?request experts to clarify the same Regards