Legal action

Hello,
I booked a villa 125 yds from canada in overseas block in btk. I paid $49500.00 us.Btk allotted me that villa in 11b # 257 and 2 months ago btk changed the map and now villa# is 60d.First of all btk promised me overseas block and charged me approx,8 lakhs more then a local client. Any one suggest me what to in this situation or take legal action against btk.