Removing online pharmacy advert from wordpress website files

When people click on the links to my website in google, they will arrive on my wordpress website with an online pharmacy advert at the top. But when people type in our website address and go straight to our website, there is no online pharmacy advert. We tried to restore the website and database to 2 months ago, but the online pharmacy advert is still there. My website hosting company suggested us to use Sucuri to scan the website and remove the infected code, but Sucuri is quite expensive. I am looking for an online security expert to remove the online pharmacy advert from my website files.