purchaser of e-auction of bank loaned property

Sir/Madam, I have bought a flat through e-auction of bank loaned property and e-auction was conducted by DRT,Chennai. I became successful bidder and got a confirmation of sale of such flat. Later I understand that some one has occupied the flat, who is unauthorized occupant and doen't have any right to occupy. DRT has issued him a one month notice which got expired by 31st jan 2015 and not received any response from such unauthorized occupant. Now I have received a copy of the letter from DRT that they have appointed a advocate commissioner for leagal proceeding to vacate and hand over the possession to me and it is mentioned in the letter that the remunaration/compensation to the advocate commissioner shall be paid by me. My question is 1. it is the duty of the bank to give a vacant possession to me and for which why should I be charged for vacating him. 2. End of e-auction DRT has collected Rs. 30200 /- as poundage fee from me.I think it includes providing vacant possession. 3. without my consent and knowledge , they have appointed a adv.commissioner for initial remuneration of Rs.15000 and I have been told that later all the additional charges towards handing over the vacant possession to me , will also be charged to me. Please let me what is the resposibility of the bank and DRT and who has to be liable for vacating the flat. Appreciating and expecting your advice and guideline. Thanks Sundar