Had a horrible group coaching call start

I have a group coaching program and tonight was my call. The first caller I took was extremely rude, uncoachable and in front of everyone asked for a refund. I don’t care, I’ll give her a refund, but how do I stop a situation from spiraling on a call in front of everyone? Do I disconnect her, mute her?

I was so caught off guard and never had this happen before. I’ve been running my program for almost a year. Any advice is appreciated. Also, how do I address this to the people who were on the call? I told them if they wanted to stay in fear or have a closed mindset I am not the program for them. I’m just not sure how to feel. I feel like I failed and I’m a bad coach. I’m in the heat of it so I know this isn’t a real truth. Just looking for some support around this.