"Follow up appointments with dermatology"

I was referred to dermatology nearly 5 months ago and was put on Isotretanoin. I was only ever given 1 months prescription at a time due to the nature of the medication and was required to go back every 4 weeks for more tests and to get the next months worth of tablets. This worked well for the first few visits, the nurse would see me, write out my prescription and book me in for my next 4 weekly appointment. My last appointment was on 20/6 and the usual nurse was not in. The doctor covering my appointment failed to book me in for my next follow up. I have since phoned in several times to try and sort this out, with no success. I have been told I need to contact Stirling, who advised me to contact Forth Valley, I have left messages in peoples machines with promises of getting a call back (which never happens) and told I need a referral from my GP (which is what was done 5 months ago) as a result I have now been off the medication for a few weeks. I am frustrated as it has not been my mistake that has caused this problem, and no one seems to be able to actually help me!