Hello, Kevin.
Quote: "...how I can get in contact with Microsoft so they can assist me?"
Log in to your MS account (the one that is not blocked, for example, through which you wrote a message on this forum) on the page: https://support.microsoft.com/en-US/home/contact?SourceApp=smc2&ContactUsExperienceEntryPointAssetId=www.microsoft.com
In the search bar, type (without quotes) "agent support" and press Enter or click on Get Help. Ignore the search results, and click on the "Contact Support" button at the bottom. On the next page, select "Windows" or "Microsoft 365 and Office" and "Technical Support" from the drop-down lists, and then click on "Confirm". Next, select the chat "Chat with a support agent in your web browser" and on the next page, enter your (the one that works) email address and click on "Confirm". A chat window will open in a new tab. Wait for the operator to respond and explain the situation to him.
Note. The chat is available during business hours and on business days according to US time.