Look at the technical support page:
and scroll down to the question about “My controller’s LCD went bad. How can I get it replaced?”.
Here’s a link to the right type on Amazon:
You can find the same thing on ebay or AliExpress for much less but then it’s shipped from China and it takes about a month to arrive.
Also, update your controller’s firmware to the latest version – they added a feature that turns off the OLED screen unless a button is pushed.