Delay in possession and very rude behaviour

Hi All, I purchased a property in 2013 and they given me in written that if CC doesn't come by 6 months they will refund my amount. After 6 months they just made my life hell and after struggling with them for couple of months i only cooperated with them and get shifted to their another project in 2014 as i was having no option at that time. Now, in this project also i am struggling the same way. At the time of shift they said i will get possession by December 2015 and I have registered agreement which states they give me possession by March 2016 with a grace period of 6 months i.e., September 2016 (i asked them at that time this doesn't match with what committed to me but they said it's just standard format we follow but will give possession before March 2016). Now when i speak to them they only give new excuses every time and tell me that possession will be given in 1 year (each time i contact its 1 year, say after 4 months i will again call them they say 1 year from there). They are not ready to give refund now whereas in agreement there is a refund clause mentioned but they deny now. They also told me that they don't have any funds to do so. I request you to please guide me what to do now?