I wanted to see what you guys think or what to do?

I'm helping out a new user who just got into bitcoin. He was at an ATM and talked to the owner and said it was a 1% fee to Sell bitcoins. The machine itself didn't have any fee information. Anyhow, when he went to proceed it charged him 20% fee or a little over couple hundred dollar fee when selling 1k of btc. Afterwards, he called the number for support but all they do is hang up even after they just talked.