Always remember, if something sounds too good to be true, it probably is. If there was a "100% guaranteed" way to stop stuttering in 3 days, it wouldn't be pitched to you by someone on an internet forum. It would be much more common knowledge and practiced by professionals. This doesn't just apply to stuttering, but everything even remotely similiar. As for stuttering, it's a disorder that still puzzles professionals to this day. So one should be even more skeptical if someone comes forward with grand claims of recovery.