The cancellation process depends on your PAC, they must provide a method for cancellation.
Drop me a direct email: email@example.com. I'll be glad to help. I live in Mexico, so Spanish is OK.
I plan to run an unconference conference session this year at devcon about electronic invoicing.
I've got some questions for you:
Who's your PAC?.
Do you know XPath?, if not, you should.
Do you know OpenSSL?, the same.