I have to download Teams for an important online call. I registered with the email and now they want my phone number. If I enter this, it says that this number is already in use.
It may well be that I've already created a Microsoft account on an old laptop - but if that's the case, I don't know my email from that time or anything else helpful. But should definitely have a teams account with this number by Tuesday.
Who do I turn to?
Since it is from Mcrosoft, maybe to Microsoft support?