In order to allow proper RadPageLayout functioning on mobile devices, you should add the following meta tag to the head section of your master page or individual page:
This will allow proper page scaling and resizing based on the current device used for browsing the respective page. Please test if setting the meta tag would allow proper rescaling. For reference how the RadPageLayout is used, you could browse its online demo and help articles. If setting the meta tag does not fix your issue and the provided resources do not help you resolve the issue faced, I would suggest you to send us an isolated runnable sample that could be used for reproducing the issue.