It obviously hasn't gone through yet or you'd have a little premium "thingy". Subscriptions bought through the App store have to be manually entered (no, I haven't a clue why...) and Billing is running a little behind theses days. The good news is you won't lose any days from your subscription; it starts when chess.com activates it, not when you bought it. I know, I know; gratification delayed is gratification denied, but you just need to be a little patient...
iOS premium activation

Anyway, thanks in advance