Can i return a mattress !?

I have no clue why my mom decided to purchase me a mattress at a ghetto place but they gave me something different then what she originally ordered. The mattress they gave us is too firm and hard. The guy was suppose to pick it up but he keeps giving us the run around. I have no clue what to do and for 3 weeks straight i've been sleeping on a futon !! What can i do?