Hello @Eddie19651 ,
Welcome to the community,
Yes you still have to pay the flex payment for your existing device, not sure whether you can upgrade to a new device until the old one is paid off, you would have to discuss this with EE customer service to see what they say.
To contact EE customer service dial 150 from your mobile phone or ring customer service for free using web based app or another phone: +44 800 079 8586 or +44 800 956 6000.
