Bought VIP's in the Wrong Order

I bought VIP membership first for Horizon 2, and then for Forza 5. I didn’t know that the Horizon 2 VIP would be discounted if I already had Forza 5 VIP. Did anyone else make this same mistake? Do you think I can get a credit for the $10?

You would have to contact MS support but as it was your mistake I would doubt it.