HOW DOW I REDEEM MY PRODUCT CODE ON PHOTOSHOP CS5 TO GET MY SERIAL PLEASE HELP THE WEBSITE IS NO LONGER AVAILABLE
CS5 is no longer being sold legally.
When did you purchase it and from where?
Sadly, you have no recourse except with the ebay seller. If they said "this would work" they misled you.
Then you need to check back with the seller.
Read this page and see if anything may help your situation. You could also try contacting Adobe (there's a link further down on this page). They may be able to confirm that you made a valid purchase.