Could you please open a new support ticket and send us the license holder's e-mail? You can open the ticket under the account of the license holder and we will check whether there is something wrong with your account. Please paste a link to this forum thread so that we will better understand the matter. Also, keep in mind that if you purchased a Developer license without subscription you will not receive new major versions as part of the Developer license. You can refer to this page for more details:
As for achieving the task with the version you already have - I'm afraid this won't be possible because the sizing logic is build-in and you can't change it. You can try to set the MaxColumns/ MaxRows property because if you have, lets say, only 2 columns your items will be wider but their hight will be lower.
If you have further questions don't hesitate to ask.
the Telerik team