Thank you for the information, and based on this, I would agree that the locksmith is your best option. Though depending on your frustration level you can certainly take a whack at it with a sledge hammer on your own, if you don't have anything fragile inside.

I'm sorry there isn't a better answer in this case, as it certainly appears to be a hardware defect with the locking mechanism.

I see you've left negative feedback for my answer, may I ask why, or if there is something I can do to better explain the situation? I do understand it is not good news to hear that you'll have to replace it, however please know this is of course beyond my control. I believe I have done my best to give you a quick and concise answer, as well as practical advice on how to proceed. The hardware defect, while not my fault, does not diminish the quality or value of my answer, so I would appreciate you changing your rating to reflect a positive one, as this is the only way I get credit for my time spent working with you in good faith to answer this question. When you provide positive ratings, I receive a portion of the deposit you've already paid to post your question here, there is no additional charge to you.