I'm sorry this happened. My experience has great with them in terms of repairs.
I will say that their repair guarentee is for only "wear and tear" so if it does seem like the bags was purposely damage, they won't repair it. Sadly, there are people that will damage a bag on purpose just so they can get the credit for something new. GRRRR Those bad apples ruin it for everyone
Are you near a Coach store? I would take it in and have the sales associate look at it and resend it in for repair (most of the time they don't charge you the $20 shipping fee too). If not, Maybe it can be repaired through a local cobbler.
Good luck!
Oh yeah, there is no need to register your bags anymore (in fact, those cards no longer come with the bags anyways).