Did him just randomly send you a message on Telegram after you joined the channel? That's 100% a SCAM!

Please do not send money to anyone other than DIRECTLY through the website. NEVER trust people that start texting you on Telegram/Discord/etc... people are easily impersonated there and all the scammers want is a new user to try to pull up some trick.

Also, they are charging over $170 because pushing a transaction directly to miners is usually really expensive. If you are receiving the coins (to an wallet you own) or if you are sending from Electrum wallet with RBF enabled, you can make it get confirmed for way cheaper.