Just got a call from this number as well, wouldn't talk, hung up. When I called back the number was an "invalid code"

This number is from Anniston, AL
I got a call from this number, yet it says it's an invalid code.
I also got another call from someone in NJ, USA and the same error came up when I called back
These two calls happened the same day.

Here's the story.
I filled out this internet form for a free survey website rewards program that says I could get a free iPad.
They called my number that I put in the website, and I told them to delete my information and to not call me. (I knew it was some kind of scam)
The number that they called me on was from Cape Coral, FL. I'm unsure if these other phone calls are because of this, but i'm planning on waiting for the phone to ring again, and I'm gonna get to the bottom of this. (Hopefully this has stopped for you after a day, because I can't stand this, it's just creepy, and i'm only 14)

got a random call from this number. no voicemail was left.

keeps calling but wont leave a message..when
i return the call its disconnected

It's a gimmick to get you to subscribe to the TV guide. They just called me. I asked her to take my cell number off the list. She would not listen, I had to threaten to sue to get her to shut up. If you call it back, it's a bad number.

Is there anyway that these people can be kept from getting cell numbers and calling people at random like this?