The water stands on the sand plate

Hello dear forum community,
After a long wait, our construction finally started two weeks ago. The civil engineer came and created the sand base. The floor slab was originally planned for this week but was postponed to next week by the shell builder. Due to heavy rainfall over the past two days, water is now standing in large puddles on the sand base and is running down one side in small streams.
Our question now is, how do you fix this? Or do you just let it dry and then repair the sand base? And who bears the costs for necessary measures? Should we as builders have protected the sand base or is it the responsibility of the developer?
Unfortunately, our construction advisor is currently on vacation.
Thank you in advance for the advice! We couldn’t find much on the topic through googling.

I find it fascinating how many experts are always on vacation.

First fundamental question: Who owns the property?

Developer or construction company?
Meaning: who is building the house: you or the developer?

I find it fascinating how many experts are always on vacation.

First fundamental question: Who owns the property?

You will laugh! But they really travel more often than normal citizens, which is probably normal given the salary

The property belongs to us and we have commissioned a construction company to build the house.

So the developer doesn't have to do anything, because there isn't one.

The next question: what was contractually agreed upon?