Floor plan of the existing house was not executed correctly. What now?

Hello everyone,
constant dripping wears away the stone and with our approach we are making progress.
( )

Now we had the floor plans created by having someone come on site to take measurements, calculate the living area, and then send us the floor plans and sections. The whole thing cost us about €1500. So far so good. However, in the floor plans the windows were placed randomly and only remotely correspond to reality. There is a door missing to the main bathroom from the bedroom and a wall in the living room that separates the office. Overall nothing “tragic” but it is simply not correct and the floor plans and the section finally cost us €600. (The price consists of floor plans + sections = €600 and living area calculation = €900).

How would you proceed? We needed the area calculation and the floor plans for the bank. That’s enough for them and my husband says he would accept it as it is now. But I’m already annoyed that for €600 we only have a very rough floor plan, which we could have had made online for €25-50...

I will upload the floor plans with the depicted errors shortly

Oh, and the stair access from the ground floor is also not correct. As I said, it’s all not tragic and I understand my husband if we leave it at that. But as I said, I would be interested in your opinion.

someone on site

What kind of "someone" was that?

An online commissioned company that advertises the execution of this service according to the Wohnflächenverordnung or DIN277. I don't think I'm allowed to mention the name, am I?

The area calculation and the floor plans were needed for the bank. That's enough for them

Sure. They usually just need something rough, roughly estimated. You could probably have done it with a tape measure or laser measuring device as well. The bags don't care at all.

But as I said, I would be interested in your opinion about it.

Yes, that's annoying. I asked before I saw the drawings... We don't know what the service provider (doesn't seem to be a freelance architect) actually offers, which suggests that he only does rough estimations. There are always swindlers and tricksters in every industry. Have you asked what he thought about, for example, the windows? Maybe you can put some pressure on him again, because surely he doesn't want bad reviews on Google?! ;) If he is persistent, I would probably devote myself to more pleasant things and put the matter aside. So don’t put too much and permanent effort into it. But if you are annoyed, then he should be too. How much effort you want to put in is up to you. There are some here who even advise to go straight to a lawyer…

Thank you for the opinion. We are looking into it. The measurements also do not match those from the measurement we have separately.

If it's only for the bank, I would leave it. But presumably you also want to make certain replanning based on this data, so I would make sure that the representation corresponds to reality.