Excess construction sand classified as "waste"

Would also be very grateful for an answer to the 2nd part of the post ;-)

Yes, exactly.
Really? Actually giving it away? For how long already? Where is the building plot? It must be in the middle of nowhere (which actually speaks against a small building plot) if really nobody is responding.
The entire amount for one person would also be a bit much, but I would have said if you give it away, everyone can take as much as they want, then it will be gone in two weeks...

So I believe you can’t do anything legally with that wording.
You can still talk to him, whether he has anything to do in the area again and could quickly push the pile with an excavator to a place where it doesn’t cause any trouble.

a mini excavator has to come (an additional 500 euro cost)

So you can move 15 tons of sand yourself with the excavator in 1 hour, it costs 100€ per day here.

And you always need sand, if necessary spread it over the entire property. I also had sand left over. And once it was gone, I already replenished it several times.

The construction site is in the Frankfurt am Main area. As mentioned, there are still further discrepancies in the invoice. Therefore, the question is, how can I be legally safe if I do not want to pay the invoice yet?

So you can move 15 tons of sand yourself with the excavator in 1 hour, it costs 100€ per day here.

Yes, here as well, but in addition: 120 for pick-up and delivery, 50 for insurance and wear parts, 80 euros/hour for the driver.

Are you in the sports club? Let the U-18 team shovel [ein Kasten Bier] against a crate of beer...