Hi, just wanted to check if anyone has made use of the "50% extra trade credit towards New Releases & Preorders New Release titles are eligible up to two weeks after launch" promo at the top of this page?

I walked into GameStop today to trade in my copy of LAD Infinite Wealth. My understanding of the promo is that it would bump up the current value of this game from $20 to $30 (extra 50%) if I put the credit towards a new game or preorder. I decided to put it towards Indiana Jones (preorder).

However, when the cashier handed me the receipt it said $20. He said the bump up doesn't apply to all used games. According to him, it only applies to a situation where I buy a new game from the store, open it there and then, and then for some reason decided I didn't want it anymore and trade it in. Is this true? Who does this? Why would they run a whole promo for such a niche situation?

I wanted to cancel the trade in but he said he already processed it and refused to do anything about it, even though he admitted he should have confirmed the trade in price with me first.

I have no idea if the promo is being deliberately obtuse, I'm misunderstanding it, or if the employee was just being difficult. Hoping to see if anyone has experience with this promo?

EDIT: Thanks guys, I took my receipt back to the store and the manager fixed it for me. She confirmed that it applies to all used games. Not sure what that other employee was doing.