Ah, turns out LittleMe Jewell managed to find the answer for me. It was that I went to the wrong island. Hadn't realized there were two different islands that look identical, with just one having blue discs on the podiums at the voice bundles. That blue disc one is the Premium center and you just touch the disc, then click the refresh for voice morphing to get the now subscribed ones activated. Thanks, LittleMe Jewell for directing me to the solution.