Yeah that is bullshit. The price match policy used to be online but I can no longer find it. It should be posted around the service desk area too. If you have trouble locating it, just ask one of the people at the desk to show it to you. It should be on a thick piece of plastic and has a blue background with white letters.
Also, just keep going back to the store. There are usually at least five different assistant manages who work at each store, so you should eventually run into one who is ignorant about the policy.
If they still refuse to price match, tell them you are going to call and complain to either the market or regional manager. When you do this, make sure to ask for the persons name you are talking to (even though it is on their badge) and make sure to write it down in front of them.
If that doesn't get them to do the price match, just call the market or regional manager and complain. You'll more than likely get gift card for your trouble and will also get the price match on top of that.