Because the ticket did say "Pick up by 1/6", I would imagine that any kind of legal action you would try to take wouldn't go far. Granted the ticket didn't say "Pick up by 1/6 or we'll throw your stuff out" but bottom line, you didn't pick it up within their requirements.

HOWEVER, I would still complain as much as possible and try to get your money back a different way. Whether it's calling the HQ or badgering the local store that did it, don't stop. If there's one thing I learned from working retail, the more of an ******* you become, the more likely the company will just give you what you want.