Too much earth excavation, too large construction pit

Hello everyone, we are building a single-family house with a basement. So far so good. Our construction expert already mentioned during the pouring of the floor slab that the excavation pit was dug too large and accordingly more soil was disposed of... the costs for backfilling will of course add up later as well. The invoice for the excavation came in, about 80 tons are too much. Is there any chance for a credit note etc... the soil was disposed of, the civil engineer is also responsible for some other trades and of course we don't want to completely upset him now. How should one proceed?

Best regards

Unfortunately common practice nowadays. I think they split it 50/50 with the gravel pits. Of course, it would be more sensible to address it directly. Was everything hauled away? Although a lot was dug out from our side as well, we left a big pile on the property until the end and only had it hauled away afterwards. We were still able to use quite a bit of it. I would normally ask the civil engineer why he excavated so much and then had everything hauled away. The dimensions of the house should be well known to him.

80 tons is probably about 60m3 of compacted soil in a basement; with a workspace, that's 15-20 cm more space around the house, that is really nothing.

What kind of soil is actually required for the foundation of the slab?

with us filling sand, compactable