Contact your dental practice and ask to speak to the practice manager.

Tell them the problems that you have experienced and ask for their help.

If they are not forthcoming then tell them you will be reporting the practice to the local PCT for conspiracy to defraud the NHS.

Our practice tried the same stunt when I had to have major work done but soon 'resolved' the situation when they thought I was going to report them.

Now have a new dentist in the same practice and am treated like royalty.