While I agree with all of the above, not all hope is lost!
Did the plants come with labels of any kind? If you search for the nursery online, some of the commercial mass producers will have a product catalogue online. If you do get lucky usually the name will be a trade name and not a proper registered name. I usually do some research on the trade name afterwards, and discover that the plant also has a proper name as well. I managed to ID my Phal Wiganiae (schilleriana x stuartiana) this way (was named Phal Philadelphia in the catalogue), with confirmation from the grower who was kind enough to reply to my email