Package not delivered and no explanations offered

I placed an order on the 25th of January. A delivery date for Tuesday the 28th (before 5PM) was given to me. I waited the entire day but nothing happened. I called many times and did not receive any details as to whether I was going to receive my parcel or not. After 5, while still waiting, I received a message saying that they were unable to deliver. I found this strange because I was at the address until well after 5. When I called no one gave me any alternative solution - I then went online and changed my delivery date to the following week. All the consultants I spoke to were not helpful at all. What is the point of a delivery date if you have no intentions of honouring it and worse, keeping the customer guessing the whole day?