If notarization isn't common in the country where you are, you should probably escalate through AWS support in that country. They probably have an alternate procedure. If you're talking to US-based support, they are used to thinking this is a trivial request. Getting something notarized is something that can be handled in 5 minutes at places as common as convenience stores. Most people have coworkers that are notaries and can do it without even getting up from their desk.

If that's not the case in your country, ask them for a different procedure. It's not something they intend to be onerous.

In Germany you can also get documents notarized in (Catholic) parish offices. I think they do it for free.

That said, this sounds unreasonable and if you're not in the US this may violate consumer protection regulations if they didn't require the same level of verification to sign the contract in the first place.