Lump-sum contract with earthworks company - still additional claim

We have concluded a lump sum contract with the earthworks company. The plot was inspected three times and no further problems were found. Even one of the neighbor's trees should not be a problem. The quantities were specified in the offer. To avoid having to check and verify everything, we were offered a somewhat cheaper lump sum contract. We then commissioned the services on a lump sum basis. It was also specified that the topsoil would be stored sideways at about 50 cm, approximately 110 m³ (service and payment via the house construction company as it is included in the construction work). However, the earthworks company completely removed the topsoil (without consulting us) (allegedly no space). I assume this was to store even more sand and thus reduce their costs. However, I no longer have any topsoil and must have at least the amount of 110 m³ transported at great expense. The tree roots were also cut, and after a lot of trouble, I had to have the neighbor’s tree felled for 750 euros. Now the earthworks contractor wants an additional 3,000 euros, claiming he can prove the additional requirement for sand and earth removal. It was precisely to prevent something like this that I concluded a lump sum contract. Should I demand the topsoil from the earthworks company and possibly claim damages?

Hello,

...Should I demand the topsoil from the earthworks company or possibly claim damages?

Unfortunately, it is not possible to give a reliable answer regarding this; for that, you would need to post the exact wording of the "flat rate agreement" concerning the earthworks position here.

Kind regards