Syncing contacts to a non gmail account

[AC Question]

Howdy, Im working on a Nexus 5x with 7.1.2, the users is not a fan of Google and is a former windows mobile user. We setup a new Gmail account as it is required to use the device, however they only want to use their hotmail account for contacts. I have it set as the contacts source however it doesn't seem to sync, newly added contacts disappear, and updates to current ones don't take. Its like when it syncs I just sets everything back to the way it was at 1st setup.

thanks!