"very very slow sending appointment out"

I had a knee problem so had a appointment with a Consultant. I was told i would be sent a mri appointment. I waited 3 months still no appointment so rang. I was told a letter was sent out but id not received it. So i asked for another appointment and asked for my appointment to be made over the phone which was agreed. I waited another 4 weeks still no call. So called back to complain to which I was told a letter had been sent out. 4 weeks later my appointment finally came through. Had the mri scan and was told that I would hear from my specialist in 7-10 days 4 weeks later still nothing so I called again to be told they had forgotten to rebook me in? I'm a self employed person who is having to turn work down due to mobility problems I'm fed up of being messed around I just want my knee sorting and still not had my appointment with the specialist