Again problem. Nothing I do everything. Play stores do not open and they told me that I don't ť have a device.
have you tried to delete cache of play store going to : settings>apps>google play store>delete cache
then you can reboot your phone and one it has done, try to open again play store.
Clear/delete cache in both the download manager and download apps
I came across this problem with a phone bought from gearbest. They seem to alter the firmware slightly. give it a go and see if it works. Did for my customer
MX4, MX4Pro, MX5e, Pro6