Below my messange also the reply from the seller.
These LEDs are not common cathode. Well the green and blue is common cathode but the red LED seem to be mounted to other way so it only works if current and ground is reversed.
I'd like a new shipment of correct, 100% working, LEDs.
Hi, Simon I'm very sorry, I know this problem. At present I have corrected the mistake, the reason is I suppliers provide goods wrong to me, and I didn't see. Don't worry, I will resend new item to your address, water clear RGB led... Hope to understand, sincere thanks! Any question can email to contact me
So lets see how the new ones work out. However the question is how many newbies like me think they themselves make an error and doesn't bother to send a message, get stuck with bad ones and looses interest because it just doesn't work?
But they're 10pcs incl int shipping for $2.99 so I don't complain.