The recent ABC Four Corners documentary reported on Scientology, and included one couple who said that at times they were receiving 250 telephone calls a fortnight, trying to persuade them to buy more books and tapes.
Unfortunately, this is what Scientology does. If they get your name, address and telephone number, you'll be hassled until the end of time. That would be bad enough, even if the comms course wasn't a recruitment tactic to get your into their cult.
On the comms course, they'll tell you you need to 'get clear'. If you do all those courses and get to 'clear'. they'll tell you you really need to do the whole 'Bridge to Total Freedom', which ultimately costs about $360,000. That's where you learn about Xenu, the alien overlord who infested out bodies with the ghosts of murdered aliens. Yes: high-level Scientology is THAT weird.
There are far better ways to overcome shyness, and they don't involve doing business with the people who are responsible for the death of Lisa McPherson, Noah Lottick, Susan Meister, Uwe Stuckenbrock and so many others.