Refusal to exchange

Good day i just wanna share my experience with telkom dawnpark after my husband purchased a device in their store and we wanted to change into white device due to misleading of the stores not having a white device. We went to change that device and was told that no you can't change to your preferred color due to their umbrella and the device is not even 7days old. I called customer service and i was advised to take it back to the store but when I did I was told no.