Tracking # isn't recognized by any major carrier. How do I check how my reader was shipped?

[SueRine]

I received notification of shipment and was given a tracking number that isn't recognized by any major carriers.  How can I find out what carrier was used for shipment.  Thank you.  

[VanKalkerFarms]

Most carriers tracking numbers don't work for 12-24 hours or more.  I believe everything I've gotten from square came USPS.