Dunns - Liberty Promenade not issuing my refund for a network locked device

I bought a ZTE device and returned withing 24hour period, but Liberty Promenade Dunns has not issued my refund even now. This occurred on the 29th of June and no action has been taken to resolve this issue. I want my refund, there were no papers signed for the device, not even RICA since this is a connection device.