Unlocked Galaxy Note 2 - locked?

I've just returned from canada bringing my unlocked Galaxy Note 2 with me. I have gotten a micro sim from tesco but when entered it will not reognise it, asking for a network sim unlock code, which seems to mean that is not actually unlocked.
Ive looked online at checking if it is unlocked (*#simlock# doesn't seem to work) and followed a couple of other methods to unlock it, but to no avail. I've also tried with a vodafone micro sim but I get the same message Anyone have any ideas, other than taking to shop to get an unlock code? Also, what would be a reasonable amount to pay?
As it was already unlocked in Canada, i really don't want to have to get it unlocked again...i've contacted my old network abroad but they are draggin their feet on getting it unlocked for me.