I was referred to NUH by the polyclinic last May f...

I was referred to NUH by the polyclinic last May for my consultation. NUH called two weeks later and confirmed my appointment for 25July. A few days later, they brought forward it to 15July via SMS. Then another day later they again brought forward to 14July. Both changes were made without consulting me whether if I could make it. When I called back to say the date was not suitable, they said you can come back next year because they are all fully booked.