So sorry that you have problems. This was not a major production like Popoff. The medium did not have any assistants or a earpiece (pretty small room, pretty crowded with 50 people). Actually she was selling a book, but maybe a couple of people bought it (she may have made like $5 off of that). In any case, you don't need to believe any of it.First off, I have problems with your assumption that the woman being a convincing actor is too unlikely to be considered possible.
That aside, you really can't come up with other ways that this could have happened?
Are you familiar with Peter Popoff? His approach (for faith healing, not communication with the dead, but still relevant) went something like this: his staff would talk to (or listen in on) members of the audience as they talked about why they came. They'd slip this information to Popoff's wife, who would radio the information to a small earpiece that Popoff was wearing on stage, unseen by the audience. The result was that Popoff would have seemingly miraculous information about people with no apparent way to get it by "natural" means.
These days, social media makes things way simpler. It's very common for a purported psychic or medium to use, say, Facebook to find out details about someone. This is especially easy if the person "likes" the person's fan page or has posted that they're going to the event.
Just because *you* weren't charged admission doesn't mean money wasn't involved. Does this "medium" sell books? One-on-one readings? Weekend workshops?