"Blamed for not receiving my appointment letter"

I have struggled with painful, impacted wisdom teeth for years and eventually managed to get a dentist to refer me last year for removal under sedation. (I'm a very anxcious patient and teeth and blocked by jaw bone) I attended my pre-assessment in February and I was told there would be a couple of months wait. I totally expected this awaited a date for the dental surgery. After six months had passed I decided to call and see how far I had progressed on the waiting list as since my assessment I've had two painful infections due to the position of the wisdom teeth. I was then informed I had not attended the appointment I had been given for removal and therefore discharged! I have received no communication informing me of such an appointment nor been informed of being discharged. Had I not made that phone call I'd still be sat waiting. After the battle to get referred in the first place there's no way I would have not attended had I known about it. As I've unknowingly been discharged I now have to go back to my dentist to be re-referred and go through the whole process again! What an absolute waste of time and money. Why was my dentist not informed I had been discharged either? I felt as though I was being accussed of ignoring my appointment date and now I have to pay for yet another check-up at my dentist to ensure that everyting is the same before they will send another referral. All because there are clearly no systems in place to ensure patients actually receive notification of an appointment. It is by no means my fault, I'm angered at the whole situation and can only apologise that my psychic ability is as poor as the care and consideration I have received here.