Most cases we see in council car parks for non-payment is because the OP was in course of paying, usually by phone, and was not present by the car. It is accepted by all players in the decriminalised regime that time must be allowed to make payment after parking, or else nobody could ever park legally ! However in your case, no payment was ever made, and to be honest, unless you tell us more qabout why no payment was made, the discount looks your best option.