This is fine content for private communications with your customer but rubs me the wrong way posted here. It doesn't read to me that your customer is being negative about Vercel in any way, so to me it feels arrogant to come here and say "well actually you can't afford us."
If you feel differently, and think it's acceptable to do so, why not instead say that on the error page? "Customer has exceeded their budget. Please add additional funds."
If you don't think such messaging is appropriate, then I'm curious why you think doing it here would be?
If you want to be truly helpful to your customer, you would consider raising or temporarily uncapping their traffic as a gesture of good will.
The “deployment paused” screen is shown publicly when hard spend limits are reached for a project. These limits are configured by the user.
Spend controls aren’t necessarily about affordability, it’s often for peace of mind (similar to a fixed price server, or a disposal card with a limit).
I also don’t view them as being negative on Vercel (we likely could have alerted them better, as it seems this caught them off guard).
Their traffic isn’t capped and they can change this if they prefer. But I’m guessing there’s some large asset causing unexpected usage, which is why I offered my email. Happy to walk through it with them and figure out a path to optimize.