My account has a random email linked to it

I wanted to change few things in my league of legends account for the upcoming the Champ Memotions Contest, and I want to make sure that my email is linked to my league of legends account. I see that there's a random email linked to it, and I can't changed it because it tells me that there's a code that I have to enter that was send to this random email to be able to change stuff in my account. Can someone help me I've had this problem since season 4 or 5 and I didn't know how to change the email. I made a video a while back showing that there's a bug stopping me from changing the email : So can you please help me with this.