Minor inconvenience vs Mexico electronic invoice hell. Our VAT is 16%, for everyone except a select group of small business, of a now discontinued tax regimen. We must issue a dual cryptographic signed XML invoice (by the emitter and the tax authority) with individualized items with ID codes from a tax authority catalog of recognized products and services, that includes tampons (53131615) to warships (25111708) to radical ecological organizations (94131701). Every invoice needs to be sent to the tax authority servers to get the second signature, without it the invoice is not valid. Without it is not possible to deduct to VAT payments, or (monthly) tax filling in general. No internet, no invoice software, no computers, equals no invoice and no invoice is almost tax fraud. A fiscal invoice is only emitted when a customer asks for it, but businesses are obliged to emit a "general public invoice" with all the sales where customers don't ask for a fiscal invoice.