Builder not started construction and asking penalty on cancellation

sir maine premia corporate city greater noida west mai 2012 mai 250 sq.ft. Ki ek shop book ki thi or jiski total cost approx 21.5 lac thi jisme maine approx 14.20lac rupees de diye hai but unhone abhi tak construction start nahi kiya hai or jab maine apne paise wapas maange toh unhone penalty clause ki bata kar 5lac rupees ki penalty katne ki baat ki.sir ab aap hi mujhe bataye ki mai ab kya karu jisse ki mere saare paise with interest mujhe mil jaye