Welcome. So you want the motor speed controller replaced? Why?
You might be able to contact someone. Their website's still up: https://fattebikes.com/pages/contact .
Too late, I have already sold it to the call centers in India and Russian the spammers.
The display is most likely a standard off the shelf one. Write down all the numbers on the back of it. Open its connector and note its color and the number and placement of the pins. Then with that ammo search google images for one and find the sellers.
Let us know how that goes. Also search for Bafang color display, images.
A couple of other things. I do not use my name or likeness. I have a goofy llama avatar and a name based on my town. If and when I do give out my contact information I use PM, private messaging. For example if you hover over my avatar you will see three buttons. The one to the right is PM.