Help documents, tickets and how to reach us.
Check the help centre first. Most routine situations already have step-by-step instructions there, which is faster than waiting for a reply.
If nothing matches, open a ticket: the symptom, when it started, what you have tried, and the domain or order number. That usually removes a round of questions.
The two ways in: self-service documentation first, then a ticket.
Two channels that do not require an existing ticket: the public ticket form and abuse reporting.
It depends on the queue and the priority chosen. Including the symptom, the timing, what you have tried and the domain or order number shortens it noticeably.
The specific symptom rather than a general description, when it started, the scope, what you have already tried, and the domain or order number. Attach a screenshot if there is one.
Changing the email address, resetting two-factor or authorising a transfer changes who controls the account. Verification is what prevents somebody else doing it in your name.
Follow the abuse page: send the domain, the evidence and your contact details to the published address. The page states the timescales we work to.