Hire a floor scabbler (a large machine that grinds concrete surfaces) they're loud, dusty and vibrate like hell but they can be used as a plane to level floors, you will need to re-finish the top with sharp sand and cement or a dedicated mortar repair product.
Hire a floor scabbler (a large machine that grinds concrete surfaces) they're loud, dusty and vibrate like hell but they can be used as a plane to level floors, you will need to re-finish the top with sharp sand and cement or a dedicated mortar repair product.