Game store refuses to honour warranty on an appliance

we bought a Samsung microwave from Game and I recently took in due to it being faulty. When I got to the store, I presented them with a receipt and warranty card (extended). To my surprise I was told that the warranty was longer valid as it was never activated online in which I asked where that information was disclosed or stated. No one could give me a satisfactory answer and I was told to go to the store I bought it from (Cresta) as I was in Rosebank. I refused to take that as an option as I am of the impression that all Game stores should operate the same and it did not matter which store I took it to. The customer service reps then called their manager who seemed less helpful and maintained that they wouldn't repair the microwave and if it were possible the costs would be borne by me unless I take the microwave to the manufacturer (samsung) where the waranty is from. I told the manager that I wouldn't do that as I bought the appliance at Game and not the supplier. I told the manager that it is the store's responsibilty to do so as the reseller of the merchandise. The manager then agreed to booking the appliance for repairs and I was told I'd get feedback soon. I received a call in which I was told that the microwave had returned and couldn't be fixed and when I asked why, I was told that it contained bugs in the inside which consumed the wiring. When I requested documentation or repair report where that was stated, I couldn't get one and the customer service rep said she'd request it as she was told by word of mouth. I told the customer services rep that I am not a technician but that reason isn't sufficient enough and i had never heard of such. I continued to tell the rep that I am even doubting my appliance was taken in for repairs based on the events leading to that conclusion. To make matters worse, I was told it couldn't be repaired and later she called to say that the report had arrived however, the cost of repairs was to be passed on to me. I questioned why, as I was still under an extended warranty and they told me to come fetch my microwave as the cost of repairs was the same as a new one and therefore uneconomical. I have been getting calls to come to the store to fetch my appliance and I refuse to do so as I am well within my rights to have my microwave repaired with no additional costs. The fact that they said I should have activated the warranty online and no one had told upon purchase is a non disclosure on their side and lack of sales training on their staff and surely that should not be passed on to me. The fact that the microwave was sent to a third-party service provider for repairs and not the manufacturer isn't satisfactory at all. I am deeply disgusted by the service of the store and will be making further enquiries on this matter as I believe that my rights have been infringed as a consumer.