Trade in from hell

Post office is not accepting the FIRST-CLASS mail labels.  They stated that the label needs to state GROUND.

I've been given the run-around with the store and the 1800 support line with. The people on the support line are useless regarding this.  They just make up things and tell you to do them.   

For instance, “the label you print that states USPS isn’t for the post office but for the store.. Take the phone to the store”