How to get user details after eBay login?

Question

ebay

Hello. I'm trying to implement registration on the site using the eBay API.
After login on the eBay side, an oAuth token is returned, which confirms successful authorization, but does not return any data about the user. Also, in the documentation, I did not find methods that allow you to get data about a newly logged in user. There is a ConfirmIdentity method, but I've never been able to get it to return anything other than an error.
Please tell me how to get data about a logged in user after his successful login and how best to organize the registration process on the site using a third-party service?
I originally intended to store the login and email (the latter is needed for mailing). On eBay, the login seems to be a unique field, but there is a possibility that it may overlap with other logins in the database (logins of users who previously registered in the standard way). The token returned as a result of authentication is also different every time, there is no point in making it unique (the next time they log in through eBay, they will not match and it will not be possible to open the profile of a previously registered user)
I would be grateful for any advice. I apologize in advance for the confusion in the text.

Answer 1

but there is a possibility that it may overlap with other logins in the database (logins of users who previously registered in the standard way).

Do something like this:
users
id, login, type_id
1, user1, 1
2, user1, 2
types
id, name, title
1, local, Local2
, ebay, eBay