Bought an apartment and handover date is Dec 2016

Hi, I bought an apartment and as per agreement, the handover date is Dec 2016 with 6 months grace period. For the past 9-10 months, there has been little or no construction activity. Now the builder is not very pro-active in committing the new dates and the penalty clause to be paid by the builder is very meagre at Rs 6/- per sqft and that too post Dec 2016 + 6 months grace period. I have tried sending emails to the management without any response for meeting or addressing my concerns. I feel even with the grace period of 6 months from Dec, the building may not get completed on time. My queries are 1) what options do i have to ensure/get my flat delivered quickly. Is legal notice the best option? 2) What is the cost involved since i'm paying loan currently and would like to figure this out 3) If i go for legal notice, Will the builder try to file false legal notices on me. 4) Do i need to be present in court or can i ask my lawyer to represent me? 5) Does consumer court or Credai a recommended option than legal notice? 6) Will it affect in future (such cases) on your onsite travel, if there is such an opportunity?