Many offline and online nurseries offer refunds for plants that die within a certain time.

I also have a small nursery and sell plants on Ebay. I send growing instructions with the plant as well as on an email to the customer, ask them to let me know if the plant goes downhill so I can help before the plant actually dies, as well as having a money back guarantee if the plant dies within two months. I have only ever had one refund request.