Land Purchase

Hi, I hope all is well. Just want to consult/clarify below. Our house is built on the land where to our knowledge it is ours (40 years), and lately, someone is telling/claiming that it is theirs which is our relatives also. Lately, they have distributed it to the relatives they call heirs, which is also why we are included but when they distribute it it goes to another relative. So they are asking us to pay, which is we are willing to pay but it is too way high? In addition to that, there is no title deed on it only the Tax declaration of our great relatives (deceased). Can you please advise? Thanks.