I haven't dealt with Rex, but with it being summer it is possible that he is on vacation or something. While it is nice to get quick responses, it isn't always possible.
Hopefully you get a response soon. I too would have expected to receive it by now.
As for GLA, I ordered a regulator from them on Friday around noon hoping it would ship sometime next week and got a shipping notice just a few hours later.
Eheim Pimp #381
Raleigh Aquarium Society Member