Withdraw from the house contract

Hello everyone. In May, we had a "non-binding" conversation with the company Okal Haus. Naively, as we were, we signed a house contract. The employee stated that the contract would only be legally valid if they found a suitable plot of land for us. After we acquired a plot of land on our own, we decided against building a house with Okal Haus for various reasons and chose a solid construction method instead. Now the company Okal Haus is demanding an amount of 10% of the total purchase price. At the time, we spoke with the consultant multiple times, and he assured us that we could withdraw at any time. He never mentioned a 10% compensation. Of course, we are extremely upset about our naivety. But is there any way to avoid the compensation?

What does it say in the [Vertragsbedingungen] about that?

The conditions unfortunately do state that a compensation of 10% is to be paid. Furthermore: "....The lump-sum compensation is not due to the company if the client proves that no damage has occurred at all or that the damage is significantly lower than the lump sum."

Well, they just belong to a larger corporate group that is certainly not delicate when it comes to the issue.

Actually known.

Only professional advice helps. Was that the standard text or did you agree on an additional reservation?

No, that was the standard text :-(

Why do you sign something like that when you actually want something completely different? Didn't you read the contract? For that amount, a lawyer is definitely worth it....