Microsoft 365 Business Standard No Adminstrator for Payment Method

Hi,

I have a strange and annoying issue to change my payment method for Microsoft 365 Business Standard as I don't seem to have admin access :

- I have a Microsoft 365 Business Standard subrscription since the beginning of the year that started as a free trial then turned into a monthly subscription

- A few days ago I had to cancel the card I use for the payment and therefore this month payment failed and Microsoft sent me an email to fix the issue

- I want to update my payment method but I can't

- To do this I would need to log in to the admin center https://admin.microsoft.com/adminportal/home?ref=homepage

- But when I log in with my profesionnal account I get a message that I am not authorized to access

- I can't log either with my personal account as I get a message that I need to log with a pro/school account 

- I somehow don't seem to have an admin account

- When I log into Office with either my personnal or pro account I have no "administrator" button as shown on Microsoft help pages

- The same pages tell that the account that buys the 365 license automatically gets admin access

- But I bought it with my pro account, I get Microsoft emails on the address of this account but It does not seem to have admin access

- This really seems weird to me as I suppose I did have admin access when I first set up my domain at the beginning of the year

- The address/account with @mydomain.com is the only one I have on this domain and I can log with the account, it just does not seem to be admin but I don't see what other account could be...

Does anyone have any idea to help me ?

Thanks