You should name the practice you are having problems with, and the exact details of the issue.
It is not fair to spread blanket coverage that ALL the dental practices are like what you experienced in the one practice you frequented.
I know a few that are excellent and treat patients right.
So please convey your side of the story and the forum will decide if it has merit. There is no NHS subsidized
care here so I would expect these services to cost more.
You can at least tell of your refund issue sounds like you feel you were entitled to.