Tax ID Update -- no support

Hi there.

I cannot add my TAX ID in the account settings workspace. Or any other place seemingly possible according to the Partner Center AI Assistant help feature, Google articles, and so on. 

I have followed various instructions for updating my TAX ID but none resemble precisely what I am seeing.

I have been trying to resolve this myself for weeks now. I have two support tickets in with MS, have followed them each up in the tickets, all to no avail.

I am part of the MAICPP, a CSP etc., and have been for a while.

As you can see, my bill information is not linked which may be why I cannot edit/add the TAX ID according to the myriad instructions I've found.

BOTTOM LINE: I do not know how to obtain support assistance from MS. Anyone have any suggestions? Thanks.