Sorry to hear - I've a house rabbit so i'm not sure about hutches - maybe the Housing section can help? I'm not sure even what you refer to with the strap - did you e-mail the company when they told you that it would be fine (aka a record of it)? What about receipts etc? It seems odd that they won't take responsibility, if you specifically asked/they specifically told you it'd be fine without any word to the wise, then in a way you have been missold the product - can you not seek anywhere for guidence on that?
I know it's not the issue though I'm afraid I'm essentially just bumping the post up cause I've no idea.