sell-off vacation "rip-off". vacation.com stole my vacation! Internet

my brother is a computer technician, and works with computers everyday for a living, and I have had a lot of computer training as well. my brother went on the internet to book a flight for my wife and myself, to go to Guyana to see her sick mother who she has not seen for a number of years, and we've saved enough to buy the tickets.
my brother went to the site of "selloffvacation.com", he selected a flight with all the criteria I stated to him, with most important of all being that we leave on the Dec.18, and return on Jan.30 2013. after finding a trip with the required dates, my brother showed it to me and asked me if that one is OK and I read all the particulars, and then told him yes (only one trip at a time shows up on the screen with a yellow button to select or accept the trip), then he clicked the yellow accept button. the next screen to appear was for payment, then after the payment was made, the ticket which appeared had the wrong return date.
we tried to contact selloffvacation.com, but got a recorded message stating that the office was closed for the weekend. I called them again at 8:17 am and was told that when the office opens at nine, they will return my call- that was Monday morning, this is Wed. night, and still no one from customer service has returned my call. (this really infuriates me).
I think that this is a classic "Bate and switch"scam. The return date for the trip they gave us is for Dec. 25,2013. Why would I spend $2,200 to travel for only 5 days?, Also, who travel on Christmas day.
They will only change the date if I pay another $1100. This is clearly a rip-off scam.
they should not be allowed do this to poor people and ruin their vacation. $1100 to change a return date they screwed-up. That is cruel. Please help me.