First, did you go to a formal institution? If you go to a private course of formal training mechanism, it will not be so simple. I spent four days, and spent money on training and learning a fingering technique (the name seems to be Yao's, but I can't remember it clearly, please search for it yourself). I'm going to open a shop in my hometown now.

Second, the effect is not that the operator has the final say, but that the customer feels that it is ineffective or the technology cannot reach home. To put it bluntly, it is "feel".

Obviously, you spent 5000 yuan, but the experience was poor. Let's just say that you didn't find the right person (professional or specialized agency). I sympathize with you!