explanation: a fool and his money are soon parted. luckily for the fool, Dept. of Consumer Affairs occasionally steps in to protect.
you should be fine. eseentially the person who posted tickets for sale was promising you that he WILL get them, eventually, when they go on sale (i suppose there is a small chance this person has comp'ed tickets, or band tickets, or some other "insider" connection). these ticket reselling sites usually have a guarantee of some sort, so either you'll get your tickets or you'll get a refund after a protracted exchange with customer service.
that's what you get for buying scalped tickets... next time just calm the f*** down and wait for tickets to go on sale, you might be able to get them at regular cost.