If you paid for it yourself
I'd suggest contacting Fredy via discord, and he would be able to assist you in private with payment issues and whatnot
If you paid another player with ingame currency to pay it for you
I'd suggest contacting a staff member (probably a Senior Moderator+) to track down the player that advertised the premium that you sent the money to, and question them about it, I highly doubt that it would take a long amount of time to synchronize the premium as I have never seen it before.