The touchscreen doesn't react to taps
All of the buttons work on my Eternity, but the touch screen doesn’t react to taps to bring up anything.
The Samsung Eternity is rectangular candy bar shape smartphone with a large display.
It may be either a loose touchscreen (digitizer) cable connection or a faulty digitizer.
Either way the phone will need to be opened and the touchscreen flex cable connection checked to see if it is OK and if so then most probably the touchscreen will need to be replaced.
Here’s a link to the ifixit Samsung Eternity Digitizer and Screen Replacement guide, which may be of some help.
There are suppliers online that sell the digitizer but unfortunately all of the ones I found say “currently sold out”. You may have better luck in finding a supplier. Just search for Samsung Eternity (or Samsung A867) digitizer part to get results.