How could I set the default contact store?
This worked for me. Try to go to Settings>Apps>All Apps>Contacts (not contact storage) and clear data.
Also try to combine all the suggestions:


cleared data in contacts app as written above
selected the display only contacts from whatever you want
made a dummy contact, selecting the desired store location
reboot


I basically tried all the solutions, so it's a little hard to give the exact way to go about this. Hope this helps.