Execution plans changed without consultation!!

One advantage, however, is when you don’t know the trades that well. It’s easier to file a complaint.

I say this way: it’s three times easier to file a complaint, but eleven times less necessary ;-)

Small update:
We have received financial compensation for the architect's planning mistake!

However, a new problem has arisen!
The basement builder also deviated from the execution plans and did not extend the waterproof concrete basement walls all the way to the end of the floor slab, but stopped about 20 cm short and then bricked up with Poroton blocks! However, this area is in contact with the ground up to the ceiling of the floor, so waterproof concrete was planned there as well!
The pictures show the problem!

The explanation was that he wanted to create a uniform façade for us ‍♂️! How does one deal with such an error?

The basement builder also deviated from the execution plans and did not extend the watertight concrete basement walls to the end of the base slab, but made them about 20 cm shorter and then built up with Poroton bricks! However, this is an earth-contact area up to the floor ceiling, so watertight concrete was also planned there! The pictures show the problem!

No, the pictures show that at the circled spot the house can hardly be dug in up to the basement ceiling, but rather this side of the house probably has exits at basement level. This does not justify the unauthorized action of the basement builder, but it does make his reasoning (having done this from his own initiative) appear quite credible and appropriate. However, I cannot find anywhere in the house plans an exterior wall made of porous bricks. Apparently, planning and work are happening quite disconnected from each other. You should issue a final directive that plans are not a basis for negotiation but a binding marching order. Who is the responsible construction manager here anyway?

No, the pictures show that at the circled spot the house can hardly be buried up to the basement ceiling, but rather this side of the house probably has exits at basement level. This does not justify the builder's unauthorized actions, but it does make his reasoning (that he did this on his own initiative) quite credible and appropriate. However, I do not see any porous brick exterior wall anywhere in the house plans. Apparently, very lively planning and workmanship are happening past each other here. You should issue a decisive statement that plans are not a basis for negotiation but a binding order to proceed. Who is even the responsible site manager here?

Thanks for your answer! The site manager is provided by the planning office, but he prefers to send invoices rather than supervise work on the construction site. How can you recognize a porous brick wall in execution plans?

I’ll send another picture showing how the sides of the house look now… because the exterior sides are completely earth-contact parts. The L-blocks will still be removed; they were only placed to secure the scaffolding.

cool they build a house 20cm smaller and sell it to you as a solution to the problem they created themselves...

The blocks are crooked and slanted too.

The insulation is detached.

That it is now built with Poroton at the front well could have been done better. Our basement is also exposed on one side but filled with mineral concrete and a drainage around the house. With you I only see clay/earth for backfilling, have fun everything that stands on the house will settle.

From now on I would hire a construction supervisor and fix the botch.

The in-situ concrete ceiling also serves as a lintel, you can do it that way but there is a risk of thermal bridging at the roller shutter box.

That does not sanctify the unauthorized action of the basement builder, but it does make his justification (having done this out of foresight) appear quite credible and appropriate. However, I do not see a porous brick exterior wall anywhere in the plans of the house.

At least the plan shows that this wall is constructed differently. The type of hatching is different, as is the thickness (30 vs 17.5 cm). One can see, and this is the problem of the original poster, that the thicker wall (concrete?) should extend forward to the building point and the thinner front side (Poroton?) fits in between. It was built exactly the other way around. This can and should be criticized, even if I don't see it as a disaster, provided it was sealed black up to the ceiling.

Nothing is built smaller there.