Spice Jet Airlines — They are charging me extra amount after booking a ticket

Address:	500016
Website:	Www.spicejet.com

I am Bharat Kumar .Spice jet is changing me extra after booking tickets .my ticket (PNR):XY2GMG . They are asking me to pay extra 570 rupees.please suggest me on this.I said then I can't pay cancel my tickets and refund my money back .they are saying that those are non refundable tickets we can't refund you.it is just like a trick of business .at first they are offering tickets for cheap and non refundable under cancellation after that they are sending messages that your ticket fare has been increased please pay 570 rupees .is this fare I already bought the tickets how can spice jet can increase ticket fare after purchasing ticket .finally cancel my tickets and refund whole amount or I fly for what I purchased