Sleepmasters useless service refund process

On 05 November 2017 i purchased a mattress from Sleepmasters. Due to the mattress being damaged i returned it on the 11th. The store manager informed me that i would receive my refund within 3-4 working days. Now its being over 2 weeks without a refund. I made numerous calls to the manager as well as the Call centre without any success. All they can say is that they are awaiting info from Head office. I've being promised to be updated with info from the store manager to the Call centre, but still have not received any feedback