IMHO I would not bother getting a GBA now as there are rumours that Nintendo are to imminently release a new upgraded version with a built in backlight and rechargable battery to compete with all the next generation mobile phones appearing with colour games capability.
I dont have any others - I cant understand why it doesn't work, I checked the email & it says that its valid until 30/11 & I haven't used it. Have you ordered from JL before ? this code is for 1st time users only. - you could try calling them - it says for problems with the code call their help line on 08456 049 049.