I can help you with contacting our support team during weekends, @simonerufphotogr
Reporting any fraudulent activity is crucial to prevent any financial loss, and I understand the urgency of investigating this matter. Allow me to provide you with some information on how to reach out to us.
If you're a QuickBooks Online Simple Start, Essential, or Plus subscriber, you can contact us from Monday to Friday, starting from 6 AM to 6 PM PT, and on Saturday, from 6 AM to 3 PM PT. However, if you're a QBO Advance user, you can contact us anytime, any day.
To receive quick and efficient assistance, you have the option to submit your this directly on a website. This will enable us to look into the matter promptly and provide you with the necessary support: https://security.intuit.com/contact-us/
Also, you can check this article for more information regarding recognizing unusual activity in QBO: Identify suspicious activity, phishing scams, and potential fraud.
Here in the Community, we value your security and welfare. Please don't hesitate to get back to us if you have further concerns about contacting us. I'm always here to lend a hand.