Repair paving works

I agree with the OP. When I commission 'paving a driveway,' the driveway starts at the street and not at any height arbitrarily invented by the craftsman.

I find it quite astonishing that the client = layperson is always supposed to be to blame for everything and not the craftsman = professional, who exactly knows what matters. Should one also explain to the surgeon before the operation how to operate and that one would like a successful treatment outcome?

The client knew about the later street level. The craftsman did not. Who has the informational advantage now? Who could have easily passed on the information but didn’t?

Sure, the craftsman could have asked about the height. But when I place an order, I at least have to communicate how the result should look.

And even as a layperson, you can go and check in the evening whether everything fits. Then maybe only the curbstones would have been set. If you are not able to do that, there are experts and site managers who do such things for a small fee.

But apparently, you were satisfied with the result for half a year. So why should the contractor have created something different?

But blaming the craftsman half a year later for the driveway not working because a height information was not conveyed by the client, I find almost cheeky.

As long as you do not post the exact wording of the written order here, it is all just guessing. Because that is what matters when push comes to shove.

Whether and who should have thought or informed is secondary as long as you do not know what was commissioned.

From experience, craftsmen often keep their offers quite sparse in order not to be pinned down to specific details. However, that does not always end well...

So again: Post the signed order verbatim, then you can see whether a liability for damages on the part of the craftsman could be derived. If it does not say something like "from level x to level y," it is almost certainly a matter of dispute and, given the amount in controversy, not worth suing.

If there is something usable in it, that does not make the lawsuit more profitable either, but you can quickly make it clear to the craftsman that a settlement would be sensible.

Was the work accepted by you?

This whole thing is a bit of a guessing game here, we also do not know what your order was... But one thing is probably true: it was not instructed by you to include the later amount, otherwise it probably would not have been concreted in.
I know it like this, that you work provisionally in the front and the craftsman does the final completion later.

Very good point! I had automatically assumed that this was not the case, but if that has also happened, most of it is already over anyway.