Incoming callers get message that my number is not a subscriber

I got a text from this number - 305-491-6143- claiming to be from T-Mobile. Text said I won an i-pad and I should enter my credit card number for $1 shipping.  After I did that, immediately a response that the prize was no longer available and I was sent to another website to choose a prize. I ended the text.   About 10 minutes later I was able to call my credit card company to submit a fraud alert, and there was already a fraudulent charge to my account! It was removed and my card closed, a new card is coming.  When I called that number on my work phone I got that ‘not a subscriber’ message - whatever it means.  The number itself is an AT&T number.