Unable to go through Activation Required

I'm in a business trip in the US and I had the worst idea to put an AT&T chip to avoid roaming charges. Now I got the Activation Required screen and I can't get through. I saw all the bars from the AT&T chip and I have wifi, but I get through the Activation screen. I don't want to reinstall the phone because I have important info. Also, its the only place I have music. Anyone knows how I could get through?