Registered road sold by previous owner to other party which is only road to get to main road

My concern is Dear, Legal advice My mother has registered plot in district patna Previous owner( has few large plot there ) register that plot with subsidiary road to main road. After few year they sold another plot including registered road( which is the only road to exit from my mother plot) to another party. I am regularly talking to previous owner to get it right. Now they told me they are changing the direction of road to my plot. Registered road has only 2 turn to get to my mothers plot. After lot of communication they told me they will registered another road which will be more wide to original road so we told them OK we will take it. Now they are offering same wide road but with 4 turn to reach to my mother plot. Many dealer tried to purchase my mother plot in less price because of road issue. I think this is the main reason to block my road so that we are forced to sell that plot to cheaper rate. Kindly suggest me what I can do about it they are just making excuses and selling plot one by one to other party. Please suggest me what should I do to get my problem solved Thank you Regards K. Sinha