Ziamond False Advertising?

Ziamond claimed that you couldn’t tell the difference between a CZ and a diamond without heat testing or weighing the gem. I called them on it and within a couple hours of my phone call they had changed their website statement. They will not give me a refund. I only bought the ziamond based on the statement of not being able to tell the difference. I have hard copies of both the original website statement and also the change they made after my phone call. I know you are the diamond guy but was just curious of your opinion on this situation.