Ask HN: How to automate?

I am a single founder and I started a start-up a few month ago and accidentally(!) I got too many costumers. I mean it was a side project just to earn some money to be able to build my main start-up. I invested 100$ dollars, 25 days of designing, coding, writing the content and marketing. In the first month I made 20.000$ and this was very motivational to advance. By the time I got much more costumers, because of uniqueness of the product spreading the word-of-mouth. Idea was simple, helping students from Azerbaijan, to apply to the internships in Germany, German universities, language courses, and so on. But because it must be a side project I must automate the process. I hired 3 guys to help me, working from their own home as the freelancers. I am the only one, who knows every bureaucratic details how to come to Germany, and at the same time speaking azerbaijani and german. I teached my freelancers how to answer to the costumers, every detail. So must freelancers automate my works, and so I can only advance the company and grow. But now I noticed, because I teached these freelancers everything about our company, they ignore the costumers contacting to us and after that they contact the costumers personally and get the work personally done. As you see, I lost half of my routine costumers. Now I can't figure out, how can I automate the process. I thought about building a platform, where costumers and freelancers can only communicate, without ability to speak with them out of this platform. But no chance, at the end of every conversations, they got the emails, and working with them personally.

Working in an office is also not a solution. Does anyone has an experience like this? I appreciate any advices.