Do as Don and Whizard have suggested and contact support to make sure it's a legal license.
If license is not valid report the seller and start a ticket on eBay & PayPal and demand your money back.
As MAPKOBKA^^ said be very weary of digital downloads for anything on eBay. I was one of those people that got burnt once.
If the price of the software is way below what the average retail cost is that is your first indication that it's probably an illegal license they are selling.
You are taking a chance whenever you buy any digital download license from eBay.
If you have to buy software from eBay the best way is to buy a new unused box version.
Best way to buy Kaspersky is from the eStore or another reputable seller like CompUSA or somewhere like that.
Good luck, I hope you have a legal license.