"Not turning up to take me for hospital appointment"

I have been using arriva hospital transport for hospital appointments I had booked transport this week for my hospital appointment. I rang at half an hour before my appointment time to see how long it would be and got told it would be here 15 minutes after my appointment time, which would of been ok then I get a call to say it had cancelled the transport and they had rang the hospital to tell them I wasn't coming and had to make another appointment which I cant get for 3 weeks this is not the first time they havent turned up. Its about the 4th I think its disgusting how paitents who need transport are treated. I think the staff need to learn better telephone manners as well with how they speak to you. I don't know how this company even has the contract to do the transport. on another time I had been to hospital and had to wait to be brought home I was ready and waiting and I finally got home six and a half hours later that night