Unless you recorded the conversation with the Rowenta employee, it will be a case of he said-she said. You can't prove that is what was said.
Also, you should report it to Product Safety but I think you should never have sent the iron itself back to Rowenta. You now have lost your only proof of what happened.
I am a real cynic when it comes to working with corporations. Do not expect them to do the right thing unless they are forced to. If this iron is a real hazard, it should be recalled.
As for the new iron - there is no way I would use it.