My Perth lash tech gave me chemical burn

So 24hrs ago I got my lashes professional done in Perth (lash extensions), this is my first time ever getting lashes. After the appointment I had a chemical burn in side my eyes from them not being completely shut throughout the service, cause of a condition I had as a kid my eyes don't fully close, however she did not make me aware that this could cause problems or give me chemical. I have had to go to the doctors for this. She blames me for not making her aware that I was uncomfortable, as in her reply she apologies and agrees that my eyes being partly open is a condensation that I was not aware of. I have asked for a refund and she has ignored my request. Please help how do I professional and legally reply to this to get my money back.