I definitely agree that I would not "trust" this OP as a trainer, given the seemingly novice mistakes. It is important to remember that, while you may be assisting a trainer in lessons to develop a horse, that is COMPLETELY different than going out on your own and calling yourself a trainer. Not saying that is the case here, but... with the complaints, it seems to be one potential scenario.
Before buying my own horse, I made it a point to look at many. I requested the owners leave the horses in the paddocks untacked - wanted to see them be caught, saddled, etc. - all from the beginning. The horse I ended up buying, the owner had saddled when I pulled up. That indicated a bit of a behavioral issue, potentially... but, she has turned out to be a pretty awesome horse. She bolted a few times when I first had her, but that was likely a combo of operator error and longstanding behavior issues - she just has a big motor and likes any opportunity to go for a run, lol. As with any horse who was trained by someone else, there have been miscommunications with my horse, but I would never fault the seller for things I 'overlooked" upon inspection - nor would I say whether or not they did or didn't use a certain training method with the horse. Their understanding of a training method may be different from my own, and they may have used certain bits and pieces of it, while I may have focused on other bits and pieces...
Hope you and your new horse learn each other! Even though
you claim to be a trainer, I hope you consider having a "more experienced" equestrian observe your work with her, so maybe you can get an unbiased opinion and help with some direction for you two :)