That is the Telegram channel in question. Surprisingly it looks so legitimate. I'm not sure what to think anymore.
Perhaps some dude registered on that channel and tried some shenanigans.
The thing is, more that one attempt to get support lead me to become suspicious.
What is your opinion of the channel at first look? Try them out with some questions perhaps.
It does look professional at first glance but I have a question for you, who is it that asked for your private key?. Is it the representative or just another person who joined the same telegram channel?. As I have explained, if you really think that it is a scam then you should just stay away from it. If the person who ask for your private key is not a representative of mynode then you shouldn't trust that person even if it's the representative. After all, it is not meant to be shared publicly. I think the person who asked for your private key is not a representative of mynode but a person who joined their telegram channel pretending to be one of the telegram support representative.