This one is different from a designer who vanishes. The agency answers your emails. They're polite, even. They just won't send the files, or the logins, or the thing you actually asked for, and slowly you realise the relationship has a hostage in it.
It's a bad feeling, and it's more common than anyone says. Here's how to get unstuck.
Read what you actually signed
Before anything else, find your contract. This is the uncomfortable part: a lot of agency agreements quietly keep the source files, the hosting account, or even the domain on the agency's side. That doesn't make it right, but it tells you what's a misunderstanding and what's the deal you agreed to. If the contract is silent on ownership, that ambiguity usually works in your favour, not theirs.
Take back the parts that don't need their cooperation
You can recover more than you think on your own. Your domain is the big one, run a WHOIS lookup to find the registrar, then try to log in directly. If the domain is registered in your name, you can move it without anyone's permission. Your content is next: copy the live text and images straight off the site while it's up. What's genuinely hard to take without them is the source code and any hosting they control, so don't spend your first energy there.
Make the request once, in writing, and keep it plain
Send one clear email listing exactly what you want handed over: the domain (or its transfer auth code), the source files, the hosting and CMS logins, and any accounts in your business's name. No threats, no long history, just the list and a date. A calm written request does two things: it sometimes simply works, and if it doesn't, it's the record you'll want if you escalate to the registrar, the host, or a lawyer.
When to stop asking and rebuild
There's a point where chasing the files costs more than replacing them. If the domain is yours and the relationship is over, rebuilding on hosting and accounts in your own name is usually faster than a standoff, and it permanently removes their leverage. The site was never the irreplaceable part; control is. That's the whole idea behind owner-of-record, and getting you out of this exact spot is what website rescue is for.
If you're in the middle of this, send what you can see, who the domain is with, what the agency has said, to info@mule-digital.com. We've helped people out of this before, and we'll tell you honestly which fights are worth having and which to skip.