If you have purchased a subscription access to time series or TMY data, you will have the option to switch to contract access after signing-in (as shown in image below).
Please note that creating an account on solargis.info is a pre-requisite for ordering SolarGIS data.
After signing-in and switching to contract access, please click on 'Purchase' option on the menu bar. You can then proceed by clicking on the "contract order" button.
Next, follow the steps outlined here. The only difference from the standard purchase process is that with contract orders you skip the payment stage of the order process.
You will receive a confirmation email upon successful completion of your order, and another email when the data will be available for download.