I've been on the other side of that argument. In my case, a client had spent $50,000 on a pretty plain static brochure website. They're not tech-savvy, so they wanted to move to a CMS they could manage on their own.

When I told them it'd be $2,500 to put their existing site into a new WordPress site, they thought I was joking. That was the day that I realized value pricing is a real thing.

In your situation (with money already in hand), I probably would've just told them "Then pay them 0.25 my hourly rate to cover their 10 minutes of work with a 50% bonus. Why are you wasting your time calling me?"