If you want to continue using Office365 and happen to move away from BaseHost who supply it to you, then you can either go to another Microsoft reseller or to Microsoft direct and take up a service with either party. The process requires you to nominate one of these parties as the responsible partner or supplier and then they have responsibility for support and billing for your account. If you wish to stop using Office365 altogether, your data always belongs to you. If you decide to cancel your subscription you can easily download your data.