Mattress exchange

I bought a bed in September in one of your branches, the bed is so comfortable but the springs are making a noise whenever I'm turning. Few weeks ago I emailed your customer service they asked for invoice number they never got back to me, I simply asked for mattress exchange cause I won't be accepting any sleepmasters till this day I'm waiting for them. Please give me another mattress the noise started within 3 weeks of purchasing it the agent said if I can go to the branch maybe they can exchange with @Sleepmasters bed.