They're reselling EC2; how can there be no servers available? Maybe they've bought a some reserved instances to get the $0.012 cents an hour cost and won't scale beyond those?
There are limits to how many EC2 instances one account can run without getting special permission from Amazon. And even when you do get permission they will only increase the limit so much. More information is available in the AWS faq: http://aws.amazon.com/ec2/faqs/#How_many_instances_can_I_run...
