"Unskilled, unhelpful and rude staff"

The appointments department don't answer the phone number supplied and dont have a voicemail so there is no way to get hold of them if you need to change your appointment. The receptionist at the hospital was incredibly rude and gave me inaccurate information. When I complained to the hospital, my complaint was ignore for 3 months. I eventually chased them and was told that they'd lost my complaint! The follow up to my complaint was equally poor. How can I take my complaint further? It still hasn't been resolved and I should have had a response to my complaint within 3 weeks, which I didn't.