Harvey Norman review: gift card received when purchasing electrical items

I received a gift card when purchasing 2x TV's from your store at lakehaven last year. I have since tried using the card in store and have been advised the gift card is not valid as it should have been activated. The store manager has informed me there is nothing he can do as the card needed to be activated within 6 months of receipt and that there should have been instructions on the card to do this (which there were not) and the salesperson who is no longer working for them should have also provided a form with the card with instructions to activate the card (which he did not). As I am a regular customer of Harvey Norman I don't find this service to be acceptable and I would like a new gift card reissued to me with the appropriate instructions to activate the card as soon as possible. I would appreciate a response to my complaint as soon as possible or I will be taking the matter further. My contact number is [protected]