I'd be interested in the steps you took. Third-party Apps on iOS can't change the Safari or system-wide options for search engines as far as I'm aware. Installing a third-party App just gives you a wrapper around Safari for browsing while you use that App only. If you swipe down on your home screen to use the system search, or open Safari itself, nothing has changed. I can ask you to install our App or another search provider's App, but it doesn't change your iPhone's search engine or add it to Safari.