Joomla! Template AT Transport - Item Support

I have downloaded Pro Standarad Package for single domain then tryed to install it on Joomla's extension manager and had this warning as a result: (JInstaller: :Install: File does not exist D:\Express\tmp\install_561cc4311e815\template\en-GB.tpl_at_transport.ini) and when i assign it as default template my web site damage
Dear Sirs,
We down loaded “Pro Standard Package for single domain”, while we needed the Pro extended license for multiple domain. The order was made by mistake, so we need to upgrade. Please advise how can do that.
Hello SARAHOB77,
For license upgrade please contact us using the following page:

Regards, AS Team.
Item Name:
AT Transport
$29.00 $21.75
Regular License
This item may be used for a single domain only.
$39.00 $29.25
Extended License