Builder's Failure of Delivery of Flat in Haryana

I booked a flat in Distt Rewari, HARYANA in Feb 2013. Before booking, the builder Salesman showed me a Ground floor flat under construction but he took me upstairs. When I asked him how come a Ground floor is upstairs he replied that the basement is meant for car parking, so my flat of interest is upstairs only haviing a good view from balcony. I came to know in Nov 2014 suring a vsist to the residential coony that actually my flat is on ground floor NOT upstairs. Comlaint about this farud evoked no satisfactory repsonse from builder-Dwarkadhis Projects Pvt Ltd. Second, as per construction linked plan, I ended up paying 95% of price withinn 3-4 mnths, namely, June 2013. He promised to me that I will get possession in 3 months as the complex looked almost complete that time in 2013. Now, whever I used to enquire the builder, he attributes possession delay to delay in occupancy certification not in his hand. This way, time has hit June 2015. When I filed complaint in the Delshi State Commssision in Dec 2014, the Presdient asked me to file only after agreement end date, namely, 3 yrs plus grace period after sign off date in Feb 2013. It means I can complain in Feb 2016 or Aug 2016? Questions are: 1) What can a buyer do when almost all builders grab 95% of flat price within 4 to 7 months from agreemnt sign-off date and postponing possession for next 3 to 4 years? How justified is this trick played by them ignored by Consumer fora/State commission? 2) What can I do about my flat which was shown upstairs but actually the unit number was found n Ground fllor which teh Sleman at teh time of booking claimed is BASMENT for car parking? 3) What is the best approach to claim my flat on time? 4) Does due to delay in handing over the flat necessiats me to pay Haryana State VAT which came into force 2 months ago for under construction flats? 5) For a flat by different builder booked by a friend, Agreement promised possession in Dec 2013 (3 yrs plus 6 months of grace period) but in May 2015, builder is demanding advanced VAT of Rs 1.75 lacs. Is the VAT demanded much after end date of agreed possession date valid?