Tires: Different tires, with reverse tread, directional arrows, proper direction

Question
I recently bought one new tire from a tire dealer, and after I got home I noticed that the tread was in the reverse direction.  Is this safe, because I was under the impression that the treads had to match.  Please help.

Answer
Paul,

Do the tires have directional arrows on the sidewall?  If so, then the tire needs to be oriented the proper direction and the dealer needs to correct this.

Do the tires have "This Side Out" on the sidewall.  If so, then the tire needs to be oriented the proper direction and the dealer should correct this.

If not, then it doesn't matter which way the tire is oriented, so there must be some other problem.  If that is the case, then I need more information.