Plot Map Price Asking

I have purchased a 80 yards Plot in Surjanj Sector 6, Pearl Villas on installment with a very high price 3 years back. Now the value of Property decrease. I have completed the payment and when I asked for possession they only give me a allotment paper on which I could not do any thing except to sell it and asking 4.8 lacs for the Map after then they will give the possession and claiming that it is SBCA fees. Is they are doing right or making me fool???