Liability of Electricity Bill till possession lies on whome?

I booked a commercial shop in Badlapur – west alongwith my 3 friends from a builder in 2013. The agreement for the said property was registered on 27/03/2015 and till now the builder has not given any written intimation for possession of it irrespective of our oral reminder after meeting their representative. The said building was completed last year only and the builder was using our shop as a godown and cutting tiles and other labour work for his other project which is situated opposite to our shop. Due to this usage there were huge amount of electricity bill came and he has not paid the same which caused disconnection of electric meter (electricity supply). Now his new project is completed and asking us to take possession and forcing us to pay the electricity bill of more than 15,000/- for reinstallation of electric meter without any intimation of possession. Even though the agreement states a clause which says that “The Purchaser shall take possession of the said shop within 7 days of the Promoters giving written notice to the Purchaser intimating that the said shop is ready for use and occupation.” In agreement there in blank space in a clause which states that “The builder/promoter shall give the possession of said premises to flat purchaser on or before _______ subject to full & final payment of consideration as agreed herein above _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ “ Even he had not kept shop in fully completed form when we went to see the shop for possession on oral enquiry for possession. Secondly he took Service tax and VAT from all the shop holders in cash and did not give any receipt at that time. After continuously asking for the receipt he said that we can only give combined tax challan paid by him. We were ready for that also but he did not give any challan giving so many excuses. Now he is speaking in a very rude manner like dadagiri and bhaigiri language and threatening us to do what he is saying. Now I want to know that Do we have to take possession without any written intimation? Do we have to pay the electricity bill which arose when the shop was in his possession? Do we have any right to take receipt for the service tax and VAT amount paid to him? And lastly what should we do now?