Users & Accounts - someone else's name?

[NNBB11]

My Sony Xperia X1 is displaying someone else's name as the 'Current User'.

Can someone explain what this means and how this would have happened to my phone? Are there ways of fixing this - is it a matter of a simple Profile Info name-change, or does it mean this person is actually now the official Admin/User (as the phone display shows)??

I do know this person - they are a recently added contact in my phone list, but how could this have possibly have changed my phone's User Name? I do not understand.

I hope someone can help as I am very worried that this is a syncing issue or that this person now has access to my phone.

Thank you

[Uliwooly]

@NNBB11

where do you see that? 

what do you see under settings >users & accounts > Users > tap on the name > do you see multiple names?

[NNBB11]

Thanks for your reply.

When I go into Settings > Users & Accounts > it displays someone else's name (e.g. Angela)... There is just her name there ("Signed in as Angela").

When I click on her name, the users displayed look like this:

-You (Angela)

-Guest (the settings button here only displays "Turn on phone calls"

-Add User

That's it.

Even in my "Contacts" app at the top it says "My Info: Angela" yet the phone number is definitely mine. It's just that it's her name displaying everywhere instead of mine.

It's very bizarre. Any ideas? How could everything associated with my name be renamed as this other person?