Missing Items ordered

I bought items and paid for them online. They delivered half the items and didn't bother informing me of anything regarding other item I had already paid for. I have sent several enquiries and I was told the item is out of stock and I will be credited with a voucher. We are approaching 2 weeks now and still nothing, no refund no voucher. On the order status they indicate that items were delivered. And on top of that I have to waste airtime waiting for customer care to give me answers. Very disappointed with their service and I am still waiting for my money back.