My tiktok account was hacked and is being used for advertisements, what can I do against this?

So, today I've been getting a whole ton of messages to my number about my tiktok account. At first it was just a random number that said my two-step verification was changed and to please check my inbox, but it didn't say what app it was changed on and believing it's a scam I left it alone. Then, I got a message from TikTok giving me some kind of verification code, and then a whole bunch of others, but I checked on have I been pwned for any data breaches and it said there were none so I just hoped it's random attempts and left it. I tried to ask a scam subreddit for advice but both my posts weren't put up because of them being "low effort"... so, I forgot about it for a few hours, but then a friend of mine texts me "Is this your account?" with a TikTok attached. At first, I thought it was a different account because the display name seemed like a username, but then I went on the account and... The username, bio and pronouns were definitely how I left them, but the profile picture changed and a video marked as an advertisement was uploaded. I genuinely don't know what to do, I've been using that account to look back on memories but mostly logged out because my algorythm was off, but I can't log back in because it says my phone number, which I used for the account, doesn't have an account attached to it.