I'm a total noob when it comes to being a web dev so please forgive me if the following sounds idiotic.
I noticed that when you search my website one of the result's URL looks like an advertisement:
It's not listed on the sitemap and when you follow the link it takes you to our homepage. I've tried to use their removals tool but it won't remove it since it's a 'valid' page.
What could have caused this and how do I stop Google from showing it in the search results?