Reluctant to refund defective goods

I bought a tire mobility kit from the store at Oxford Village in KZN online and paid for delivery.

The item arrived, and when I tested it, it wasn't working. I decided I would retest it a few days later. The next day I drove my car I realised that the 12v cigarette lighter in my car was no longer powering my phone charger and deduced that that might also be the reason the compressor didn't work.

I proceeded to buy a replacement fuse and replaced it. All good, phone was charging again. I plugged in the compressor and it immediately blew the fuse again.

I then contacted the store and JJ said it needed to be collected and tested. Well, it has been collected, over two weeks ago, but still I cannot get a refund or in fact even communication of the progress of testing. I mean, how long can testing really take?