support.google.com
support.microsoft.com
support.apple.com
EDIT: I should clarify that none of my examples use a ticket system. Instead, they have support articles and search. The content is very SEO-able.
https://support.apple.com/billing
https://support.google.com/a/answer/1224185?hl=en
https://support.microsoft.com/en-us/microsoft-store-and-billing