Replying to I just got a letter from paypal...

So I just got a letter from paypal telling me I got denied for like a credit card or something from a month ago but I never applied for one.

And it said my credit score was like 390 or something but I've never had a credit card or a loan in my name. I literally should have no credit at all.

What the fuck should I do? I've never applied to a loan or credit card. And I should have no credit at all. So why do I even have a credit score and how was I denied if I never applied to anything??