Consumer Redressal

I ordered a Springfit Posture Collection Dx Mattress Order ID:6241801137 from snapdeal.After 6 days of booking i got a mail regarding cancellation of my order.As i paid the money upfront and got confirmation mail from snap deal earlier.When i checked the item to rebook it they increased the price. I request the authority to put a check on the online sellers as they are not keeping up with the promise made to customer.