As Amazon starts winning fat government contracts for unaccountable sums of money, it will probably care less and less about offering "value" to its smallest private sector customers.
The only constant with tech support is that it's highly variable and depends on many factors. Enterprise MSDN/SQL support is not bad though and you should've gotten a quick reply if you're using the proper channels with an appropriate support plan.
You get an account manager rep and upon occasion, interactions with AWS engineers, depending on what you're doing and how exciting it is.
One might say a lot about AWS - but I don't fault them on the customer service front for a serious business spending serious money.