Hi all, Nice to meet everyone here. I am a newbie. I have some questions to ask and sincerely hope some experts can enlighten me ?

Based on an scenario only, lets say I engaged An SEO agency and pass them all my cpanel password to bring up a website ranking in google for 6 mths, and after 6mths, i stopped their service. QUESTION:

1) Can they deliberately bring down my website ranking ?

2) If my website ranking dropped in google by a huge amount after I stopped their service, isit more of a case of google or more of a case of the SEO AGENCY ?

3) What are the things I should be aware before engaging an SEO agency ?

Thank you so much guys.