I know that this can be really difficult, trying again and again and being completely disappointed.
I would imagine that you've had at least a few email exchanges with ladies prior to meeting? In my experience, an email or two prior to a session can really clear up any sort of "mistaken identity"; in emails, I expect to be treated as a peer and treat my potential client as a peer, not as a potential submissive. Being able to discuss wants, needs, likes, and dislikes in a pressure-free manner is important. In my case, it allows me to say "yes! I'm into what you're into, and I think we will have a great time!", or "no, i'm not into what you're into, but here's a list of a few ladies who might be able to help you". Also, while you may have thought you communicated clearly, often times, communications get crossed. Being able to write things via email allows for clarity; it also allows me to look over something prior to a session in order to refresh my memory.
I'm honestly curious about what your fantasy consisted of and why/how 4 separate instances left you disappointed. It sounds like the ladies you contacted weren't proficient in BDSM practices and the idea of limits, or if they were, they simply didn't care. In the first case, one can learn. in the second case, one shouldn't be offering BDSM if she's not interested in it.
Either way, I hope that you keep trying, whether in your personal life or with a professional.