Before reporting
Reload the page, and check the relevant troubleshooting article — many issues turn out to be a setting rather than a fault.
What to send
Steps to reproduce it, what you expected, what happened, the screen or link involved, and a screenshot. The exact wording of any error message helps a great deal.
What happens next
We confirm we have it and try to reproduce it. If there is a way to work around it in the meantime, we send that first.
Anything affecting bookings
Say so clearly. Problems that stop customers booking or paying are prioritised.