"Awful dermatology department"

I am on tablets which are prescribed every 4 weeks so I have to see the doctor. I have been on the tablets for 6 months but have had a 3 week gap each time I finish my 4 week course due to no appointments being available. Every month I have to spend half a day at least calling the switchboard, the reception, the call centre and the secretary to try to inform them that I have not received a letter or text for an appointment and I'm coming to the end of my course. Each time I am told they will call me back and they are sorry, each time someone is off either a consultant or a nurse or some other excuse. The service is awful and although I desperately need to stay on the tablets I am feeling it is more hassle than what it is worth and I have been told today that the next appointment available is in May! I give up!