Bank Sold Fake property through sarfaesi

Hi, I recently purcahsed a plot from citibank, bangalore through auction. After registration of sale certificate, I came to know that the property belongs to some thrid party and not to the borrower who had availed loan. Events are as follows Landlord A sold site No.49 to B mentioning dimension as 30x50 Landlord A sold site No.49 to C mentioning dimension as 30x40 C got to know about earlier transaction b/w A to B C sold to D taking EC for site 49 with 30x40 dimension D realised cheating by C, availed loan from Citibank by depositing title deeds. Citibank sold to me through public auction. Now B is obstructing me to enter property. Pls note , while taking EC if we dont mention any dimension, it will reflect all the above transactions. But if we mention dimension as 30x50, it will reflect only A & B If we mention 30x40 , it will reflect A, C, D & myself. Now I have informed citibank, asking for refund of amount. Because citibank doesnot have a title to sell through sarfaesi. Title of property belongs to B in legal terms. Anybody can suggest some remedy