If they were an authorized dealer for the products in question, selling with a manufacturer's warranty (i,e., not a grey market item or used item without a transferable warranty), the fact that the warranty card might not have been sent in shouldn't matter, and the manufacturer should honor the warranty--you should check the warranty information that came with the equipment for the limitations on the warranty, though, to make sure they're not applicable. The dealer's promise to make all repairs, of course, won't be too helpful at this point. A sad story, unfortunately. My local dealer went through some tough times during the last recession, but weathered the storm and is now thriving, albeit primarily through home theater and multiroom installation work.
Insolvency
I have visited and bought from a small high end shop for the last two years. Just today I went down to the store to buy some accessories. The store was dark and the front door had a sign on it: "Insolvency sale delayed until Monday because of sickness." I was shocked and sad since the store was run by two trully passionate long-time audio hobbyists into vinyl and nice tube gear. It was different, innovative, carried hard-to-get equipment from small, underground manufacturers. Here is my question: over the years when I bought a piece of equipment from the store, they would keep the warranty card with the promise to take care of repairs if the item broke. Now that the shop is gone, I have several pieces of equipment whose warranty I am unsure of. Will the manufacturer repair if I just show a receipt from an out-of-business audio shop? I assume that I will not be getting any of my current orders from this shop (luckily, I did not give them any cash deposits in advance). Have any of you had similar experiences?