Certifying

I contacted this supplier to install a gas geyser, I had to arrange the plumbing to be done separately form the geyser installation. When the acceptance was done for the installation I paid for it and asking about the certification as his ad on gumtree stipulated he supplies certification when installation is complete. On completion of the work I paid him in full taking is word when he stated the certificate will be ready in one week. Since the installation I constantly asked for the certificate but did not get any response, about a month and a half later I received a letter stating the installation is legitimate. I continuously contacted him via e-mail &amp