Recover Hacked Facebook Business Manager

My Business Manager was compromised and I’m locked out of the entire account—pages, ad accounts, everything. I have no idea how the intruder got in (Facebook shows no clear trail), and the only step I’ve taken so far is opening a support ticket through Meta’s Help Center... (Budget: $10 - $30 USD, Jobs: Account Management, Computer Security, Facebook Ads, Facebook Marketing, Security Auditing, Social Media Management, Web Security)