How to Repair Soft-crete Subfloor

In the process of removing old vinyl in my bathroom and kitchen the very fine top layer of the soft-crete subfloor came up. My installer told me that they could not lay down new vinyl because the surface was chalky and crumbling. At the advice of Loew's I filled the damaged areas with rapid set CemetAll. It filled in the damaged areas, but I could not get it very smooth and the areas are now bumpy. How do I get this subfloor ready for new vinyl - smooth and level? I can remove the CementAll repaired areas, but then what other product could I use?
Thanks so much - Kyle
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