No Account, No Pay !

I have written several times to *** (as per their website: https://www.capetown.gov.za/General/Contact-us) in order to obtain outstanding invoices so that I can pay them (willing to pay if only I can get the relevant invoice), But I get absolutely no response. By the way, the e-mails were flagged for delivery receipt and read receipt acknowledgement, and I have received a delivery receipt from my e-mail service provider.