I prodded @FrontierHelp on Twitter about the server issues we experienced in the past week. They asked me to open a support ticket about it, so I did. The response to that the next day was "that was server problems", as expected.
Today I got an email asking me to fill out a Customer Satisfaction Survey, which I did, but on hitting submit my browser displayed:
for https://support.frontier.co.uk/pages/survey-thank-you404 Not Found