Here in Canada when they "forget" to change a price they are bound by the law to sell it for the lowest stated price. Most businesses now have access to the internet and should be checking for what is posted. I've had this happen when buying my bbq. It was lower online and they had to sell it to me for that price. It was also a case of "someone didn't change the price". I've had a few times where they don't change the sale price the following day when the sale is over. I'm quite quick to remind them that they have to sell it to me for the low price. 

Well, they wouldn't budge and I don't feel like declaring war because Mr. Sue needs the services they sell.

So, he bought the $999 package and they lost my business...and I hold a grudge...for a REALLY long time...one of the more charming aspects of my personality.  (ie..I will never spend a dime in there.)  

".and I hold a grudge...for a REALLY long time..."

Bank of America screwed me over in 1983 and I still won't do business with them...