If the therapy was anything like what you describe, it was definitely NOT state of the art. This is also the case if you and your parents were told that you had the kind of stuttering that responds to treatment, unless it was a reference to stuttering following a brain injury of some sort. I would strongly recommend that you find a support group for people who stutter. In the US, you can go to westutter.org to look for one in you area; however, local groups have been meeting on Zoom, so you could attend any meeting. I run one of the groups; I would be happy for you to join us...