import D2L to Moodle as a course

I am looking for a way to import a Desire2Learn (D2L) course to Moodle. The D2L course is in IMS format. 

I couldn't restore this IMS package to Moodle as a course as it is not recognised as a valid Moodle backup. Attempt to rename the zip file to mbz and imscc yield no positive result.

The only way is to add it as an IMS resource, but it then becomes a single activity in Moodle.

Does anyone knows of any conversion tool or ways to migrate D2L course to Moodle? Any advice is much appreciated. 

Thanks.

Allison