Account hacked…any advice?

Anyone had their account hacked and gotten it back successfully? I changed my account to private and someone somehow got the verification codes from my phone and email to remove them from my account and change everything from a Chinese made phone (not one we sell in the US) in California. Worst part is I had videos on there of my cat who’s passed and now that it’s private, I can’t even watch them. I put a ticket in with TikTok but there’s nothing specific for accounts that have been hacked. I didn’t have anything super important on there but still. Annoying and makes me worried about my phone’s safety in general too.