It's not a soft tail, that term refers to a very specific design that has a small, short travel "shock" on the upper part of the seatstays, usually of the elastomer type I believe. Several manufacturers made them, although with the advancements in rear suspension I wouldn't be surprised if they're extinct.
I'm nitpicking, I know, but as far as the terminology goes, what you have is a full suspension mountain bike. I'm not going to comment on any maintenance, etc. that you should do to the bike's suspension, there are too many designs and products out there, so I don't know.
And I agree, you should have bought a hardtail. In the lower price range, a good, new, full suspension mountain bike doesn't exist. To make a good one, it costs more-
EDIT: Moots still makes their soft tail. Here's what I'm talking about, notice the small suspension device on the upper seatstays:
http://www.moots.com/#/product/bicycles/mtb/ybb/