How do I contact in person a recurring billing with my late husband live XBox account?

Good morning Wendy, I am very sorry for your loss, and the headache this issue is causing you. I have checked through Microsoft's official page on related matters and found this section below:

If you do not have access to the account
Ensure that any subscriptions to Microsoft are cancelled. You may stop any subscriptions to Microsoft by closing the customer’s bank account or credit card, revoke authorizations or informing the bank. Outlook.com and OneDrive accounts will be frozen after
1 year and any email messages and files stored on OneDrive will be deleted shortly after. Microsoft accounts expire after two (2) years of inactivity. For more information, read section 4 of the Microsoft Services Agreement.

I have had to deal with a similar issue with a different service, and I had to go the route of calling my Credit Card company / Bank and revoking the authorization for the recurring charge. It should be no issue as the charges are on your card and under your
name. Microsoft has strict security on the accounts and it is very difficult to get access, even in the worst of situations.

I hope this helps, and I apologize that there isn't more I can do to assist.

How did you accidentally switch it to Serbia? And, where are you... USA? Regardless, since you have already done a migration in the last 90 days you would have to contact Xbox LIVE Support so that they can escalate your issue to be resolved by a higher
tier of support. However, if you are in a country or region where Xbox LIVE Gold Memberships are NOT available, you would need to stop recurring billing, otherwise, your Xbox LIVE account will remain active but it simply will not work. To find more info
about stopping recurring billing go to
support.xbox.com/.../cancel-xbox-live-gold-subscription or contact Xbox LIVE Support.

Please access this link Cancel recurring subscription charges | Xbox Support to get more information on how to cancel the subscription.

If you are unable to cancel your subscription, Please contact our live support:

Contact us | Xbox Support

Hi WellingtonLuis1,

You want to contact Xbox Support to stop the recurring billing if you can't access your account

https://beta.support.xbox.com/help/subscriptions-billing/manage-subscriptions/cancel-recurring-billing-or-subscription

Hello Travis,

Thank you for your post. Please refrain from posting personal information on the forums. I understand you are experiencing an issue cancelling your subscription, please check out the following article for steps on how to do so:

Cancel Recurring Subscription Charges. If you are unable to cancel the subscription, please use the
Contact Us portal to speak to an agent.

I hope this helps.