You need not return the range extender. If I can make it work with the aiport, anyone can. I bought the refurbished one, and despite the directions to follow the network configuration card enclosed, THERE WAS NOT CARD. But FEAR NOT, I figured it out! I don't even know what WPS stands for.
Here is what i did
on the airport utility base station-->Add wps printer. I selected that and pressed the WPS button on the extender. The light on the airport then turned COBALT BLUE, a color I did'nt even know it had and then voila (almost) there flashing green light turned into a solid green lightg
NEXT- I could then get into the extender configuration wizard and set up passwords for the extender, also change the network SSID thing--it assigned "old network name-->2.4g" or "old network name--> 5 g"
Finally, somewhere in there there is a choice to input the password for your wireless network so that the extender 'logs in" to the apple airport extreme. I did that and it worked like a charm.
I know these directions aren't using the right tech vocab, or precise, but they worked and i hope it saves someone hours of work. Please let me know if it works!
Happy extending~
dm