Can you work on a cryptocurrency exchange platform?



For several weeks I have been in touch with several so called fiverr developers to create a platform where users can buy and sell cryptocurrency from the admin just like, but it has been a detastesful experience here on Fiverr.
Most of these so called quack developers end of wasting my time or stop responding after they realize that they cannot deliver on the job. This makes me to wonder if there are real competent developers who know what they are doing here.

In summary what I want to create is not that too complex, Is simply an exchange with BUY and SELL order form for cryptocurrency (See, A members area with two level verification system. First is phone verification using sms just as when creating a WhatsApp account (applicable to all users). Second is document upload verification which raises the daily transaction limits.

Any good developer with similar experience should pm me.