You will stay on hold for a while but be transferred to an operator that will put in an infopass request for you. This request will result in a call back some time within the next 72 hours. They only call once, they don't leave messages and you pretty much need to guard your phone.
When you talk to them be very clear that you need an infopass due to USCIS error and be rehearsed in explaining to them exactly what is going on.
The people who book the infopasses always say that they can't be done online anymore to free up space for those who "actually need it."
You actually need it.