The key contractor on a billion-dollar wastewater plant in North Vancouver is firing back at Metro Vancouver after the regional district said it is scrapping the project’s contract. The district recently said contractor Acciona Canada appeared to have “abandoned” the project. On Friday, it said it had “no choice” but to terminate the deal, accusing contractor Acciona of having “failed to meet its contractual obligations, which include delivering the project on time and within budget, as required under the initial fixed-cost design-build-finance model.” On Sunday, Acciona responded, claiming Metro Vancouver owed it millions of dollars.