Staples **DOES** blacklist people who use coupons and pricematching. It happened to me and I finally changed my ID and got a new customer number. I have to do that every three months to stop the harrassment.
What happens is that whenever you order, it gets kicked out automatically and you are not notified. Then they send you the stuff you used to bump up the price for full price. If you call and catch it, the thing you wanted is then "out of stock." I got screwed for a long time before I started doing simultaneous transactions on my brothers account, that's when it became obvious.