The 22-year-old star admitted the culprit has been collecting some strange memorabilia to try and make some money through the auction site.
According to UK newspaper The Sun, she said: 'The other day I was up north and there were these - well, I don't think they were fans actually, they were like eBayers.
'I'd be at the venue, they'd be there. I'd leave the venue and they'd be there. Then they started taking pictures of my dog doing a s*** and stuff like that. It was really weird.'
The Grammy-winning star added: 'I was on my own taking Louis out for a walk. One of them just got in the lift with me and I got really panicky. Luckily there was a cleaner on the floor I was on.
'I was just thinking, imagine being someone like Cheryl Cole or Katy Perry or Gaga, where you've got to be conniving to have a normal day. That scares the life out of me. I don't think I'd be able to carry on doing music if it got to that point.'