Sell Agreement and power of attorney

Hi, Recently am planning to buy a residential plot in sec-72 noida. Mr. X got this plot from noida authority via lottery system in around 2003 and this was sold to Mr. Y and his wife via sell agreement in around 2004. On the same day on which this plot was sold to Mr. Y, there is a Power of attorney on the name of daughter of Mr. Y made by Mr. X. Can Mr. X gave power of attorney to daughter of Mr. Y ? And now, one time lease rent is on the name of daughter of Mr. Y and I've even checked with authority and they are saying double fees for transfer will be charged and daughter of Mr. Y will do all the proceedings. We are dealing with Mr. Y and even we are paying to Mr. Y and they have even got the completion certificate from noida authority in last 5 days and even Mr. Y is saying that my daughter will do all the proceedings of transfer and registery but your sell agreement will be with me. Property dealer is saying this is a case of GPA. Please guide, is the above process right.