Irrevocable Power of Attorney

Hi Myself Nirmal Shah. My uncle sale land in 18/2/1997, on basis irrevocable power of attorney which he had on 17/8/1995. He got this power from six landlords of land. Out of six one lady ( who is mother of other 5 landlords) had died on 7/7/1996 but other 5 landlords didn't inform us. They all gave us irrevocable power for land whether I can do anything, like sale, non agriculture permission on behalf of them. And on that basis we sale land to other person on 18/2/1997 and that person sale that land to third person on 31/1/1997. After all this, six landlords filed complaint against us in Collector office, Gujarat Revenue but their application did not entertain. And they gave order in our favor. After all these matters, now they filed police complaints on basis of power in which they mentioned that Land can be sell after Non Agricultural permission and misused of power after death of one lady ( who is mother of other 5 landlords). So please let me help, what can I do? Is it criminal or civil matter?