Need to add concrete back to my basement floor but not sure what concrete mix to buy at Home Depot

Crappy contractor who built my house ran off on me when he started building French drain to prevent my basement from flooding. It was warranty work in a new built house. Took him to small claims and had trial this past Monday but won’t get verdict until two weeks.

In meantime I want to refill this hole back with concrete. I have gravel and will add it first along with a water barrier. But not sure what concrete mix to buy from Home Depot? I dodged a bullet by him not removing the wall footer as that would have caused integrity issues with my basement wall🤔

https://imgur.com/gallery/tvglYqt