iPhone not activating (read story)

I just bought an iPhone and I live in Mexico, so the options is either enter credit onto it or have a "plan" where you pay every month for the calls and internet you use (3G) so I still can't add credit onto it. then I selected my country and language and internet on the starting iPhone manual, but then it syas "Could not activate your iPhone, this serveice is temporarly unavailable" and so I connected it to iTunes. Nothing happened, it just says that iTunes Store is currently unavailable. I am very impatentient and I really want to use my iPhone