On Darkorbit I started with a Premium Membership but I never bought it so how did I get it

Don't trust those text BIG SMS to 5934650 because all you're doing is paying for Uridium through your phone company after someone buys it.

On certain days, logging in or registering will give you premium as a special event. Also, after staying off the game for roughly a month, Darkorbit will send you an email. Logging on after receiving this Email will give you 30 days free Premium, 10.000 Uridium, a banking doubler, and 100 Jackpot Dollars.