Well, it's clearly his fault for not reading faq. And I believe that nutaku sends e-mail if your gold is about expire (like one week before it expires), so it's also his fault for not checking e-mail.

It's really hard to pity you since it's your fault for not reading faq or e-mails. Although it would great if gold was permanent but guess what! Nutaku isn't the only one with premium currency that can expire. So next time how about reading faq before you buy anything? This way you can avoid many unpleasant surprises.