Online Auction Bid Was Apparently Per Item In The Lot Instead Of For The Entire Lot, Now Being Charged Double The Winning Bid

Location: we are physically in Connecticut, but the auction is online.

My wife is a goat farmer and recently won an online auction for goat semen. There were two separate lots for semen from this buck that were both listed as "qty: 2" (2 straws). She won one lot at $550, and the other lot sold for $500. Now she is being told that she owes them $1100, because her bid of $550 was actually per straw. This was not made clear in the listing, nor is it clear in the website's terms and conditions/auction rules.

For some context, it's fairly standard to buy multiple straws of the same buck, so there was no reason to think that it was odd to be bidding on two straws at the same time. In fact, the other multiple-straw lots all follow roughly the same trend of $150-$300/straw (e.g. a lot that listed 4 straws went for $1200). The customer service person that my wife has been dealing with mentioned that he'd received several phone calls after this auction with the same complaint. It seems that even if there was something buried in the listing or in their terms, it was not clear to a lot of people.

The people that run the auction website are offering to the next highest bidder, but failing that - is there any way out of this, or are we going to be out $1100?

EDIT: Thanks for everyone's input - it sounds like we'd have a decent shot at winning the legal battle if it ended up in court, but in the interest of maintaining good relationships with other breeders my wife is probably going to just pay the $1100 and call it an expensive lesson learned. I'm more of a "let them sue me" person myself, but she is the one whose name is actually attached to all of this and would be the one dealing with it. Thanks again!