Got full set of tips lasted over 3 weeks and wonderful service

I purchased a gift certificate 16 days ago and went in for a fill today. They tried to say that it was expired and accused me of changing the date. They were extremely rude and disrespectful to me. I immediately went to my office pulled up my credit card statement and printed it off. I then went back to the salon to show when I had purchased the certificate. The woman would not even look at it and would not apologize for her behavior. I am appalled at how I was treated today. D- very unprofessional, poor business ethics. Yuck.