Concrete is wash away!? So our concrete which was done by a company who is...

So our concrete which was done by a company who is presently out of business. The problem is the work they did(our concrete) is now wash away! The concrete is not solid if it rains or you sweep it, it comes sour like a powder! I dont know if they mixture be weak, but the ingredients didnt bond. I be wondering if there be anything we could do to fix it! Please HELP!
What can be used to verbs severely textured...
Answers:    Before you think around busting it up, try a good clear concrete sealer. It might be that it be overtroweled and the top 1/4" or so is weak, thus it flakes sour.
Take a pump up hand sprayer 2-3 gallon, put within your concrete sealer and spray over concrete according to the directions. This might cure the flaking and dusting on the surface.
I am sure the concrete is solid, it is just dusting rotten the top thin branch.
Let it dry good beforehand you walk or drive on it.
My DE pool filter it not really filter...
Sounds resembling they mixed it too dry. I don't know how big an area your discussion about, but you would probably be better past its sell-by date breaking it up, and pouring it again. It's either too dry, or too much sand, and not plenty cement. There are some epoxy sealers that are very tough. But if it's breaking rotten with a broom, I don't believe they will hold it together to long. Sorry!
My neighbor have a resourcefully drilled.?