A Delivery Service worse than Royal Mail?

Mr. / Mrs. Amazon,
Please tell me why you insist on using the worst couriers in the known universe (Amazon Logistics is NOT a proper courier and neither is Yodel or Hermes for that matter) and why you repeatedly make promises re:delivery that you are not able or willing to fulfil? I have placed several orders with you over the last 6 months and the vast majority of them have been incorrect or late. Please tell me which definition of the word 'guaranteed' you are using when referring to "guaranteed delivery" - I am unable to find any source which defines 'guaranteed' as 'possibly, but only if nothing goes wrong and only providing the delivery driver has more intelligence than a Brussels Sprout.'
By any definition, In the civilized world  a guarantee implies that the guarantor will offer recompense if the guaranteed event does not occur as guaranteed - your best it would appear is to "extend" by one month the worthless "Prime" membership that I do not have (it is still in trial and you have failed miserably to show me that Prime has anything that could possibly be described as added value (I have no spare time to read books from the Kindle Lending Library or watch streaming video as I have spent the overwhelming majority of my spare time calling your customer service representatives.) as it has proved to be even worse than your normal delivery arrangements - at least when I pay for next day delivery, I get a refund for each time you screw it up. Simply put your prime service offers Love film streaming, a truly awful delivery service and the opportunity (actually more of a requirement it would seem) to spend a considerable amount of time on the phone to someone who keeps saying "I understand" when they so clearly do not. How Amazon is able to so consistently fail to deliver on the promises they make amazes me. Arguably, what is even more amazing is why I've let Amazon do this to me again and again - the answer of course is price and availability. Although your credibility is fast disappearing, you are still marginally more trustworthy than the internet equivalent of a "man down the pub". Whilst you may not loose me as a customer entirely (where else can I get random computer parts for a reasonable price?), I am not impressed and when e-buyer becomes more competititve, I'll be off.