5C is unlocked, so it should work. Did you try a different SIM? Also reboot the phone.
I only tried the SIM of the employee who swapped it from her Vodafone iPhone 6. That particular SIM was the one that caused my phone to read 'No SIM.' Also, we did try the hard reboot (holding down both buttons) with the SIM installed, to no avail.
skyline1010, thanks for those details. We reasure you that your device is already unlocked http://vz.to/1rOQDDy However, you will need to reach out to your local wireless provider for assistance with provisioning that phone to work on their network.
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