Yeh, they don't like to give refunds for faulty lenses and will resist unless you are assertive and persistent.
Instead they try to get you to send both your camera and lens away to the manufacturer, and if the lens is not 'found to be faulty', they don't reimburse your postage, they charge you return postage + additional inspection fee from the manufacturer.
I have purchased a number of other things off them, but after the hassle of my faulty Tamron 17-50, I wouldn't buy anything like a lens or camera off them, as it's not uncommon for such items to need adjustment, which is normally available under warranty.
Edit:
As your buying a 10-22, I guess the lens shouldn't have trouble with AF accuracy, so you should be ok...