"No appointments"

I have been under Darmatology since 2011. I have never before had a problem with getting my appointments sent out to me in the post seeing as I am on Isotetranoin and have to go back every 4 weeks to have a review and another months prescription for my tablets. It is only in approx. the last 8 months that there are just no appointments available and I find myself ringing up a few times every week to try and get an appointment booked in with no luck. I am now trying to get an appointment after last being seen on 24/6/15 and still no letter sent offering me an appointment. I have tried to get 6 weeks at a time so I dont run out of my medication like I have this time. It is ridiculous and frankly I am starting to get quite annoyed at the fact I have to chase my own NHS appointments with the hospital when it should not be like this. If it is not sorted I will be putting in a complaint with PALS because enough is enough. I am sure I am not the only person who needs monthly reviews with the doctor. Please improve your service as I have had no problems in the past it is as I said only in the last 8 months.