I’d say just bring to a different centre. Sounds like somebody doing more than their job requires. All the info is on the paperwork coming from the country of origin. If they want to take the car apart to see something it should be at their expense.

If your asked for it again say it’s on the paperwork, if they won’t Vrt the car say fine and don’t leave until you have something in writing saying they have refused to take your money. They won’t be so smart then.