Hi @Malin Katarina Runsten (student, 20maru1) ,
Please note that Microsoft Office 365 Accounts is not supported in the Q&A forums. You can find a complete list of supported products at https://learn.microsoft.com/en-us/answers/products.
I would advise following the Reset a Forgotten Microsoft account password steps. If you are not successful following those steps, please contact the support team.
Regards,
Ryan