Hospital referral rejected

I was referred to the hospital for a knee replacement. I waited two months for an appointment, two days before my appointment I received a text reminding me of the date and time. I arrived at the hospital and was told that I did not have an appointment, I showed the receptionist my letter and text. He then said 'you have been rejected!' I asked how this had happened, he said that I would have to see my GP.
Had this happened to anyone else? How did you deal with it? Why wasn't I informed before I needed to do a 26 mile round trip? My GP surgery is looking into this but surely this is unacceptable? I think that it's a way of reducing waiting lists and causing delays