How do you cancle a subscrition for Seventeen magazines without cancling your old one?

Okay so here's the thing, I've seen the freebies sweepstakes in their magazines all the time and I decided to try it for once. Last night i entered the contest thing and when i hit the submit on, this conformation thing popped up saying "thanks for entering and your 10 magazines for $10 will be sent to you" or whatever. the point is i don't want the 10 magazines for $10! i tried canceling it but im not sure if it will cancel the subscription that i have right now or the '10 magazines for $10' one. one of the options also said that i can "expand the current subscription by 2 issues without any extra cost". does it still mean that i have to still pay the $10 or no? if not how to i cancel without losing my current one? HELP!