POA agent made self sale deed of property

Dear sir, Mr Srimurthy came to us as buyer for our undivided hindu family property in Bangalore central which is of 2160 sqft.and made registered sale agreement for only 1284 sqft. and consideration of 1.75cr and only made 2 lakh advance in form of DD.and rest some 48 lakh as cash for legal documentation like khatha dispute of same property in 2016.and sale consideration for 3cr.later he convinced us for POA & took a registered poa from us to represent us before civil bodies & courts.and mentioned for sale term also in 2018 January.and assured us of full consideration on POA time.once poa executed he cited a short of money reason and promised to pay rest during sale deed execution.cunningly he made self sale deed himself in 2018 Oct. cheating us for our consideration in which he had mentioned cheques of worth 2.25 cr with different dates and different amounts in our family members.which we have not received at all. and made sale agreement for 4.36 cr to third party can we revoke the POAnow.