Block Checkout URL to be re-used

We have a problem that some people are re-using the aborted checkout URL to create a fake order every time.
We know the IP Range they are coming from and tried to block the traffic but as soon as they use VPN they can open the checkout URL again.

After we decided to add the app “Blockify” where we were also able to block VPN access but unfortunately, the VPN blocker allows direct access to the checkout URL.

Does anyone have any idea how to block these aborted checkout URL to be used again and prevent those people to create lots of aborted checkouts.

When we try to connect to our website through VPN we get the error, because VPN not allowed:

But when adding the direct checkout URL it allow us to connect?

Thanks in advance for the support.