It looks like Imagine moved away from using Pixelmags as their Apple iOS developer sometime in late 2013. The following message appears in the "Version History" notes of a number of their apps (iCreate, Web Designer and Total 911, to name a few), all in December of 2013.
* Important - following this update you will be required to restore your previous purchases and re-download your issues. This app is no longer supported by Pixel Mags therefore your Pixel Mags log in details will not work. We apologise for any inconvenience this may cause.