@briankrebs I ran into an IVR today like this.
Someone signs up for a T-Mobile reduced rate thing called Assurance wireless., but they used my email address by mistake.
I call their number to get them to fix it and it asks for my mobile number, but gives me a way to bypass.
2 layers deeper it asks again, I again bypass using the audible prompt.
It then says "Thanks for calling" and hangs up on me.