Please explain this question, it is about Agency Law

1. Miss Roberts is a director at Derby Consulting Ltd. (DCL), a company based in Christchurch. There are five other directors in the company but as none of them live in Christchurch, Miss Roberts ends up undertaking the day-to-day management of the company. Miss Roberts enters into a contract with Epsom Advertising Ltd. on behalf of DCL to provide e- advertising for the company. Epsom Advertising Ltd. provides a successful e-advertising campaign for the company. It then invoices DCL for its services, but DCL refuse to pay arguing that Miss Roberts had no authority to enter into the contract on its behalf as she had not been appointed its managing director. Advise Epsom Advertising Ltd