Hi there, I have the old display (mobile phone style) my bike is a 2015 so it’s the older px motor. I connected mine as the instructions and it work as it should. Gives the wrong info in mph mode but it’s correct in kmh!! If I’d have known this I would have gone with a different system. Having said that it works ok and assists me all the way to flat out, well as fast as can pedal anyway.
I would send it back for a refund if I were you. I purchased mine directly from speedbox and the guy I dealt with seemed very good. I saw them on eBay for a few pounds less but I’d rather buy from the manufacturer at least that way if there any problems you can go back no problem. If you followed the instructions to the letter I can’t think why it wouldn’t work. Does the display change at all when you activate it? If not it’s either a wiring fault or the unit is dud. But the plugs can only go one way, I’m saying that as it did on my installation, foolproof really.
Send it back and order one from speedbox, I’m sure there will be faults as there are in all electronics, but when it’s working it’s good!