I wanted to send them feedback online through their website to let everyone know of this shitty incident but my comment was rejected as 'spam' (and yes, I'm at my boiling point as I write).
This was what I intended to say:
Please bear in mind that racial prejudice is simply unacceptable and will not be tolerated. People like myself come to you because we are concerned about our health. We pay you for your services and that includes courtesy towards your patients.