Dual twin SIM card adapter doesn't work on T-Mobile Samsung T309 - HELP!

I recently purchased (on ebay) one of those "newest" dual twin SIM card adapters . Unfortunately I cannot make any use out of this adapter. I have a Samsung SGH T309 T- Mobile cell phone. I believe I installed the adapter properly. I placed the original sim card on the sim-1 side and together slid them back into the original sim card slot on the phone. The new sim card I put by means of the metal clip onto the sim-2 side of the adaptor. When I power up the phone the ONLY information I get is at the home page - it says "SIM-1". The ad said, "Easy to switch between numbers online with an easy user Menu created by your phone menu system when put into the dual sim card adapter" Unfortunately I get no such menu. The phone will not switch to sim-2 even if I shut it off and then turn it on. Furthermore, when someone calls the phone # on sim-2 the phone does absolutely nothing. They get voicemail, but I have no way of knowing that someone tried to call. Can you help me?

I'd say give a call to the seller, I have no knowledge of these adapters.

Maybe someone else knows?