Originally Posted by
jdrtravel
In the future I would suggest that you simply enter the Sky Priority line and proceed until you are turned away. When someone turns you away, then ask where the STE line is, and explain that you understand that this is a benefit.
Sounds as though OP neither tried to assert the use of the lane or to speak with someone from DL on the spot (99% of problems are best dealt with on the spot).
At best, OP will be reminded that DL does not guarantee all services at all airports as per DL's website and at worst, he'll hear back something even more bland.