You may have switched phone service during the middle of your billing cycle with your former phone company. Based on this, the carrier will send you a bill for the last days that you had service in order to close your account.
If you received a new telephone number from Time Warner Cable, you need to call your former telephone company to cancel your former phone service. If you did NOT call your former phone company to cancel your phone service, you may be receiving bills from your former phone company because they still consider you an active customer. Please call your former phone company to cancel your service.