how can I tell if my phone was hacked iPhone

My phone was ringing and it showed that "Sophia" was calling. I don't know anyone by that name and was going to decline. The "decline" option was grayed out. I figured I'd let voicemail pick it up, but it never did. I eventually lost patience and answered. Someone was already talking on the other end in a foreign language. I immediately powered down my iphone.  Is there some way I can find out if it's been  hacked and clean it out without reseting everything?

Thanks!