I am Having Trouble with my Sign-In ID

So, my brother was trying to log in to our account today. He said none of the passwords we use are working. No biggy, we can just change the password. So I click the triangle to change the password. Our email is already in the box by default. While it's loading to send an email to change the password, it comes up with an error message, "The information you entered is not valid." Great. I went back to make sure there were no mistakes in the email, everything was correct. Out of confusion, I logged into my email to find an email that was sent on august 7 from PlayStation. It said my Sign-In ID had been changed. Neither me nor my brother remember changing, and we are the only ones that use it. It gave me a link to tech support in case I did not intend to change it. I tried to contact them through phone, but apparently the service is currently closed. So does anyone know what I can do to get back our account. I'm getting really impatient with this, I did not planning on doing this garbage.
tl;dr: Sum1 stole me ^soul acownt. Send halp.