If you value the business of selling them, it might be best to chalk it up as a loss and send more, free of charge. Good customer service can only help spread the word (if that's what you would like), but he may just bad mouth you if all you do is request a refund for the dead roaches minus shipping as you did ship it.

If somebody personally said they'd *try their best* to ship it on Monday for a Tuesday delivery, i wouldn't be waiting around unless I got confirmation that the person was indeed sending/sent the package.

Who knows, the loss of some roaches could mean more business if he talks to his friends and gives them your info. If it's expensive to ship them, you could ask for just shipping costs and you would send what he ordered that died + some just to show you value their business. You never specified on the amount of roaches/cost, but if you're trying to expand the business/side job, whatever you want to call it, 1 bad experience can turn away several potential buyers. Remember, its not the truth, but how it's spun!