This is very strange. I can not find an answer to this. On Sunday 12/05/16 i had my computer on using photoshop. I used it for a few hours and turned it off. On Monday 12/06/16 I got home from work and had an email from Ebay stating "MC999 Unauthorized use of your account -- Action required" I had to reset my password / phone number and finally got into MyEbay to look at the messages. On 12//05 Ebay had sent that message but after someone had bought Microsoft Office 365 - 5 uses per month. I then got paranoid and checked my computer and sure enough someone installed Microsoft 365 on my computer during the day on Sunday 12/05. How can this happen or be?
Do you remember seeing any update activities or doing any clicks to confirm some action on your computer?
Are there any additonal/new installations on other computers on your network?
How much were you charged and where did the billing come from - i.e., the payee?
I have a 5 User MS Office 365 subscription for which I pay $10 per month via automatic credit card payment to Microsoft. I can manage the subscription and the use of all 5 licenses via Microsoft's website.
Just do not see all of the necessary actions etc., happening via some trickery much less some inadverent click.....