"Terrible telephone operating system!"

I have an appointment booked in for November which I can no longer attend. Thought I would call well in advance and cancel so not to inconvenience anyone and so that someone else could attend instead of me. I have been trying for 3 days to get in touch and have spent 50' on hold in total! Absolutely disgusting as my letter states that if I don't turn up to appointment I will not be able to reschedule one in the future!