Harassment due to spicejet flights cancellation.

I had booked two-ways flight for two persons on 26th September via spicejet from Kolkata to Port Blair on 4th March with flight no. SG 104 and return on 9th March, 2015 with flight no. SG105. My PNR no. is KCIN4H. Total booking cost was Rs. 12000 only. Today I was told that both the flight have been cancelled.
I requested the airline customer care to either make alternative arrangement in another flight of any airline on the same day or refund the amount needed to book new tickets. Refund of only the amount I had paid for booking the flights won’t solve the issue because we have planned the entire vacation in Andaman with hotels and travel agency booked and payment has been done too. But all flights via other airlines now cost more than Rs. 30,000 which I can’t afford. At the time of booking, these flights were available for Rs. 16000 only. Still I went with spicejet as tickets were available for 12000 only. Had I known that the flights might get cancelled, i would have been happy to pay extra 4000 to other airlines, rather than paying extra 20000 now. It’s a big harassment for us to have the tickets cancelled with entire tour already planned and paid for. Why should I pay extra 20000 now for no fault of ours? I am a student and can’t afford such a high cost of the tickets. So kindly help me make them arrange alternative flight for us or refund the amount required to make new booking.