At this point, if you are going to hire Oracle, the proverb of the Frog and the Scorpion applies.
I have never worked with a company that bought Oracle products, but I still have a bad experience from their presale calls.
If you say you're not going to answer in a positive, then you also shouldn't answer in the negative.
So replying once in the negative reveals negligable information and probably does not risk identifying the vendor at all.