Wow, I am SHOCKED that you got that response from Lands End. I used to work at a Lands' End shop and we never would give you that response. I'm wondering if Lands End changed their policy, I think that Sears and therefore Lands End is suffering.
I would say more about this, but I'm trying to keep my mouth shut, but I can't tell you how shocked I am that the customer service rep told you this. I would call Lands End again and talk to another sales rep and see if you get the same response. Talk to someone in person.
I would return the backpack, it should last longer than 2 years. As someone who has worked a lot in retail, you have a legitimate concern and I would return it. You would not believe what people return.
I looked up the return policy on Lands End's website and it does not seem to have changed.
http://www.landsend.com/cd/fp/help/0,,1_36877_36883_37024___,00.html Guaranteed. Period
Really call another customer sales rep. I think that they will be as suprised as I am at the response that you received.