
I do not see where it is asking you to buy the game again. It clearly says your account status is active and is asking for your Steam account information.
Maybe I am missing something as I did not go through the middle man Steam for this game.
Edit: So basically try entering your Steam account name. It looks like the site here is not coupled with your Steam account.
That adds important information. Is that image Zos' website or from Steam? It looks very similar to Zos' site except it has the Steam Edition section where I have information on how to install the PTS.
@ZOS_BillE may be more familiar with whatever page you are seeing.
@uriangelub17_ESO
Is ESO actually showing up in your Steam library through Steam?
Our FAQ below has some troubleshooting you can use to check if Steam is linked correctly.
How do I make my Steam version of The Elder Scrolls Online Steam integrated?
@uriangelub17_ESO
If you've not done so yet, go ahead and open a ticket with customer support so they can check on your account entitlements.