I don’t think so, but you may say “garçom” to get their attention.

In Brasil, if you don’t call your waiter/waitress they are not coming to your table.

It stopped what Trump couldn’t.

They’ll just mine it elsewhere, we’ve been down this road before.

If you keep saying no to invitations, people will stop inviting you. See if there is something you can do to enjoy going out a bit more, that should help you say yes more often.