In some cases, if you used domain with @qq.com as registration email, there is probability the server rejected your access. If you try to reach out for support via contact form using qq.com domain, any outgoing emails from @elementza.com towards @qq.com will be rejected and marked as unsafe. To register and make sure you have access to your files, unfortunately you´ll need to use different email provider. Please contact me via Facebook or Twitter in case you don´t get any reply to your question.
There is no limit.
After purchase you will get immediate download access. But, in case you closed that page by accident, please check your inbox (and spam folder) for My Account login info. Form there simply login into My Account with provided data, and go to Downloads section.