It seems the Commerce Commission has finally managed to prosecute a text trivia provider for something, and the company TMG is refunding all subscription payments made for their 8555 premium message number.
So, if you ended up paying these guys money, you can get a refund from http://text8555.com/refunds/.
Way to publicise the Commerce Commission decision though - it seems the midnight ads are specifically scheduled to reach as few people as possible so they don't have to give any money back.
And good luck prepay customers proving how much money you paid them. Surely either this company or the telcos (VFNZ and TNZ) could dig this up off their own systems? Seems a bit dumb expecting people who don't get bills to provide proof of payments to one short code.