As I already told you, when you bought our plugin, there was a refund policy:
,,Once we have distributed a release version to a customer, the sale is final, and you may not return the software for a refund. " .
But, if we don't fix your issue, we'll give your money back. But, first of all, we can't give your money back if the product is working. We're very sorry, but if you don't let us give support, we are not able to help you. As other 70+ members, why can't you trust us? Nobody had the website crashed after any installation of our products, so if you have any problem you can request support using our forum or our contact form anytime, not requesting refund right after you bought it.
Also, regarding support: Can you tell me what jomsocial version are you using and what sh404sef version are you using? What kind of problems you had after copying the plugin? Have you tried to purge the results and wait for the new url's?
regarding the invoice...I just made a test order, got the invoice right after I pressed ,,checkout"