What does the hotel usually go for? If it's not in the area of $22 a night, then you knew it was a mistake fare and you probably knew this was going to happen.
Travelocity is doing the right thing by letting you know ahead of time. They could have said nothing and you get there and the hotel just tell you no when you get there.
I'm sure there will be tons of people who don't agree with me, but if you knew the rate wasn't realistic than you can't possibly expect them to honor it, you were just hoping it slipped through without being noticed.