This was a voice call that was not completed (and Unbillable Rules are configured to SPIN this unbillable code).
Common Resolution(s)
Actions you can take to resolve the problem:
This may be configured to SPIN just to provide visibility. In this case this record can be left alone (it will eventually age and no longer be visible) - or it can be purged immediately if desired.
If the usage record should be billed anyway, choose Override Rule on the usage record. If this is done frequently, consider a change to Unbillable Rules for this Unbillable Code.
Details
These are calls that were not answered. Service providers often BYPASS this type of usage when it is unbillable, but in this case the unbillable rule configuration caused it to SPIN.