(If you've been following my other posts, we did get updates to work!)
I managed to have it work once, when I ran the script, but when I attached it to the button, it didn't work and gave me an error message about SQL errors )
Looks like that instead of using an id (I'm guessing a number) to determine which record to remove from the database, you're trying to use the entire selected row object.
Maybe {{Contacts.selectedRow.data.id}} is what you're after?
Ah, yes, I keep forgetting I added an id now. Thank you!