I reckon it's great your pic is being used...regardless of payment.
Yes, it would be nice to receive some form of compensation, but this instance should be viewed as something you can list on a CV (or whatever) as you continue to compile photo credits on your journey toward perhaps one day being paid for your images, if that's your ultimate aim.
I've contributed many pics...even articles...for publications, for which no payment was received nor asked for.
Sometimes it's just nice that they made it out into the daylight, beyond my camera's memory card.
