As far as I know, the lifetime licenses no longer exist. The most you can get is a 3 year license.
$35 is not good at all for an internal license. You can get an external license for around that price all day long, or even get a yearly license directly from cPanel for $35/mo. Some datacenters offer the internal licenses as cheap as $19-20.
As far as the email delays, that doesn't sound like a DA issue at all. DA wouldn't be in business if everybodys' emails were delayed for days. Sounds like an issue with your mail server, or a configuration issue.