cannot clear sample text/logo!

http://www.natalieannephotog.com

What shows up on admin page is not what shows on the internet for some people who have viewed my site. On cell phones, the sample logo “Late August photography” shows up instead of my purple, pink, grey logo “natalie anne photography.” Some people are seeing what should be there. why is this happening?? Do I need to change some settings for mobile use?