Personally, I would demand 100% refund at this point (actually, I would have reached that point long ago). His refund policy doesn't matter since he has failed to keep up his end of the transaction, which was to provide an enclosure and deliver it to that first show. It really sounds like you're being taken for a ride, and if you aren't then the seller would have offered a full refund some time ago because that's what responsible sellers do when they can't hold up their end of a deal. Having problems in one's life is a perfect reason to take some time off and work through them, but is absolutely not an excuse to jerk people around. You're being treated badly.
You used a non-secure payment method, which is never a safe plan when engaging in a financial transaction that has you paying for goods that you have not yet received, but you may be able to get your funds back through some other part of the transaction chain (if the account is funded by a credit card, for example).