Glad to hear it turned out well. I know this kind of situation happens quite often.
Having worked at
Walmart, service desk no less... if somebody throws a big enough fit management will cave. Being only a couple days past the grace period, they will surely do what it takes to make the customer happy. Especially if they have a receipt AND sealed in the box...obviously they are not trying to scam the store. I would honestly be surprised if management wouldn't approve the return.
Of course there is the "no receipt" route... that would work, the money would be put on a gift card and you only get so many of those per year (If I remember correctly it is 3). They go by drivers license number.
Best policy is to be honest about it, and talk to a member of management.
Funny thing is, if a "lower member", like the girl working the service (is probably a cashier in rank) desk approves a return that violates policy, she will be in trouble. However, if somebody goes higher up, usually the next step is the CSM chances are they will approve it and it makes the lower level employee look stupid for being petty. If the CSM doesn't approve it, they can speak to a member of management, and usually the magager WILL approve it no matter what. That makes the underlings look bad, but they are just doing what it takes to stay out of trouble.
The higher up you are, the more flexibility you have with the rules. That is probably true in any company.