I got at least 10 stations with just the antenna adapter plugged in. Did you check the plugs? Any damages, e.g. is the small middle pin there on both sides? Did you check the antenna adapter with a multimeter to make sure it's not broken? And btw, what car and what RNS-E?
i'd prefer to not list the sellers name because they are handling this professionally and I wouldnt want to make them look bad because it isnt theyre fault. Everything but the radio works on the unit. (SD, NAV, etc..)