If you bought the interface used, you'll need to contact the previous owner to have them remove the registration.
If you bought it from a dealer and it was sold to you as new, you'll need to go back to the dealer to have them rectify the situation.
You can also contact support at https://support.presonus.com
, you'll need to provide your proof of purchase and the dealer you bought it from.
If you did buy it used, you are not guaranteed the bundle software that it originally came with. You can purchase Studio One Artist in the shop.