Amazon SA fails to keep it's promises.

I am going to try very hard to shop online anywhere other that at Amazon SA. I will give you my latest experience, but this is not the first time I have had this happen. Amazon promises to deliver goods the day after the order is placed. I got an email and SMS from Courier Guy and from Amazon saying that my goods would be arriving on Friday. It was inconvemient, but I waited at home, only to get messages from both Courier Guy and Amazon saying that they were "unable" to deliver. I checked my phone logs and no call had been made to the number on my profile. I complained to both Amazon and Courier Guy. They promised to deliver today, but the same "unable" to deliver message appeared on my phone. This is extremely bad service. Courier Guy has performed very poorly, but my contract is with Amazon and it is up to them to manage their service providers