I went to a well known spa for the day at Christmas. I am allergic to a very specific chemical, and wrote this on my medical form before I had a treatment. The lady did the treatment but then used a final product which contained the chemical, and it burnt me. 
I spoke to the manager and they arranged a refund and some tea and cake, and I asked that the staff be trained to read the product labels and medical forms before doing a treatment.
I went back to the spa this weekend and EXACTLY the same thing happened but with a different treatment, except she used it to start the treatment and had slathered it on without even looking at my form. My skin is burning and I have itched all night. The manager was horrified and offered a refund of the treatment (which hadn’t taken place as she stopped immediately) and a free spa day but I’m not keen on returning now, as you can imagine!
What should I do?