I usually don't wait more than a week (at most) after realizing something doesn't fit to return or exchange anything because having been in retail myself and being a consumer, I'm aware that rules are there for a reason. I also am aware that health codes differ from state to state and change from time to time.

When I first moved to North Jersey, the health codes and all store policies clearly stated no returns on undergarments and swimsuits (both with signage and on the reciept),regardless of the package condition. A few years later the law was changed, and unopened undergarments were excluded.

I was also in management for about 9 years, and there were many times I overlooked rules for "customer satisfaction", but the flip side of that was if the manufacturer wouldn't accept a RTA or RTV on it, the loss reflected poorly. You seemed reasonably flexible in your request for an exchange and if it means keeping a customer, I hope they reconsider.