You need to explain this in a lot more detail. It sounds essentially impossible to provide this service with zero-knowledge encryption, but I'm open to being wrong about that.
https://ironcorelabs.com/blog/2023/announcing-encrypted-ai-e...
Saying "we use a similar approach to Cloak AI" isn't good enough for many reasons. They don't provide a lot of detail to begin with, so it's unclear their approach is proven. And you're not even using their approach, just a similar one.
Even if we had a long whitepaper about how you do things, that's still not good enough because we don't know that you're actually doing it. That's why the audit is important.
You can read more about Homomorphic Encryption here: https://aclanthology.org/2022.finnlp-1.4.pdf