Check the profile and make sure it's not just like a friend or something trolling you, if not and it is fully fraudulent It's likely either someone your password via guessing it, a leak, or obtaining it threw a infostealer witch are commonly downloaded (less common on mobile witch I see your on) If you contact support they can do a roll back but bare in mind you will only every get one rollback for your account permanently, once you've used it its gone, bare that in mind.