"Appointment delays"

I had a tumour removed 3 and a half years ago. Appointment were  supposed to be every 4 months but it got to six months when got appointment sent. 

Sitting in consultant waiting queue for 1 hour and half not getting seen on time, so had to leave. Now appointment which I say is to be 4 month still hasn't arrived. It will be over a year if I get to  see consultant about my tumour but I think I'd like to complain and go to another hospital. I've been treated badly it's a shambles.