How to fix my iPhone 4's camera?

Okay well this is my third iPhone in just little over a year. The first time I had to get a new phone because of my home button so that was covered under warranty. I got it in April. The second time I got it replace was because my lock button wasn't working, and that was just a week ago. When I went to apple they told me that my year warranty was up and also the other phone I got that was a 90 day warranty. So then I went to Verizon and it was covered by insurance and they gave me a whole new phone for free. Well now the phone they gave me, I have it for a week now, when I go onto the camera there's a splotchy brownish/black dot. It's inside the camera, I can't just rub it off. Now I'm not sure if I should go to apple or Verizon to replace it. Since apple didn't give me this phone will they still do the 90 day warranty on it? And Verizon I'm sure I could be fine with. What are thoughts? Or if there's anything that i could do?

Take it back to Verizon. Get a Android next time.

Take it back to Verizon, youve probably been given a refurbished phone thats not quite right.