Builder Delaying the project

Hi , I have a concern here as my builder is delaying the possession of the flat and the initial handover date was June 2014 as per the construction agreement and now there was no sign of construction being progressed and the builder is giving many false reasons for not constructing the building and making many false promises.The building has 15 floors and only 14 floors were constructed without any tiling /painting/Plumbing works. No progress has been made for the last one year.The builder is saying now the handover date is Nov 2015(Which is practically impossible as there is no work going on now). Questions: 1.If i need to go to consumer court should i file the case within 2 years of the dispute arises ?In this case the deadline is June 2016 as the original key hand over is on June 2014.Are there any issues if i go to consumer court after 2 years? 2.I lost some of the payment receipts from the builder is it required by the consumer court? 3.What are the documents required so that i can win the case as i have paid all the installments properly? 4.Should i file a case with consumer court singlehandedly or jointly with other flat purchasers in my buiding ?Which has more advnatage for the case to win?