What is this?
Thank you for the question. This plant is definitely not a primrose lilac. Instead, it looks like a sedum of some sort. There are many different varieties of sedum so I can't tell you for sure which one it is. Sedum are in a category called succulents because they have fleshy leaves that hold water. This makes them good plants for rock gardens and other sunny, dry areas.
Here's a link to a local garden store that lists popular varieties of sedum along with photos. Maybe you can identify it, otherwise, call the the vendor you ordered this from and see if they can help. http://plants.gertens.com/12070009/Results?