VERY BAD MR PRICE ONLINE EXPERIENCE. PACKAGE NOT DELIVERED BUT PAID FOR

I ordered 3 items online and when I went to track my order a few days later the order status was delivered. I called the call center to query it and the consultant told me the driver says it was delivered at 6pm the previous day and I signed for it. We were not even home at 6PM the previous night as my family and I went out for supper. Its been 3 weeks and I dont have the package nor a refund. I have called 4 times and the call center agents keep saying that its being investigated but nothing is progressing.