My PS6 Extended requires signing

Hi all,
Is it possible to determine to which account PS6 Extended serial numbers have been assigned?
After updating Windows, my PS6 requires signing in, but I don't have a product assigned to my account.
I have 2 PS6s and I can't use either of them.
I bought the program in a store in 2016, unfortunately the store recently closed its operations and I do not have any support from them.

Thanks for your help