I have an ecommerce site, but I am not using PayPal. However when you search my company name in google, the PayPal check out page is displayed as a site link. You can then click through and go to a checkout page.
I haven’t set up PayPal
I can’t see anyway of disabling the PayPal checkout page
In the editor the message "PayPal is disabled and will not be visible or functional on your published site’ appears.
Exclude this page from site search results is checked
Sorry that’s happened to you. It does mean that at some point, somehow, google found the page on a crawl.
You cannot really get rid of a sitelink easily. But you can demote it which usually will eventually get rid of it. To demote a link first the site needs to be available to you in google search console. Go to the Search Console home page and select the site you want to edit the links for. Click Search Appearance to expand this, and then click Sitelinks. In the For this search result box, complete the URL for the page you don’t wish to display a sitelink. In the Demote this sitelink URL box, complete the URL you wish to demote. It will not happen immediately, does take a little time but that is the best way to work with a sitelink you don’t want showing up.