Footer editing

Whoever can help me I thank you in advanced. I have been trying to edit the text in the footer of my website but it has been to no avail. I went in to appearance>editor>Footer.php and I deleted the part that I did not want to appear in my website which was “Powered by WordPress. Designed by WildWeblab.” After I deleted it, when I click to visit my site, it looks exactly how I want it to look, however when I logout, it goes back to showing the text, and it looks like I didn’t do anything to the site. I have tried clearing the cache, but it has done nothing. I am not that familiar with PHP so it is definitely possible that I did something incorrectly. If someone could help it would be greatly appreciated. The theme that I have is “Icy” by WildWebLab