Rental clause in Construction agreement not adhered

The developer had promised to hand over my flat by the month of October '17. However, it has not been done and the construction is still in progress. Was told that the delay was due to the shortage of fund. I have a clause in my Construction Agreement as below: The First Party shall under normal conditions complete the construction of the building/Flat and agree to hand over possession of the Schedule II Property with basic amenities like lift, car parking and security on or before April 2018 however subject to availability of cement, steel and other essential items on construction and also subject to unforeseen events such as Acts of God, Earthquake, Floods, war or other local disturbances, changes in laws of the state, corporation or any other clauses beyond the control of the First Party. If Second party is delaying during any of his customizations at the time of delivery, and first party is interdependent on the second party tasks to be completed, in such cases, the above timeline will be considered upto handed over to the first party first time only. In the event of delay by the FIRST PARTY/DEVELOPER to handover of the possession of the Schedule II Property, then the FIRST PARTY/DEVELOPER agree to pay the prevailing rent 12000/- per month as liquidated damages to the PURCHASER till the handing over of possession. I would like to know how I can initiate a legal approach, if I am not paid the promised amount.