Unscrew the SureFeed and see if there is a short circuit on the circuit board or if an electrolytic capacitor has burst.
It's not difficult to dismantle the device.
I also had to disassemble and repair the old SureFeed.

It is a fact that this model gives up the ghost after 2-4 years.
I already have the fit bowl, two have already gone out this way, if the third goes out after the same time, that's it for this manufacturer! It is more than noticeable that the devices are already on the blink after 2-4 years!
Unscrewing to check if something is defective is an operation, once it was enough to clean everything and lubricate the many moving parts with silicone spray. I wouldn't recommend this, however, because it ruins the chance of getting a replacement unit. In addition, it is a tedious fiddling job to reassemble everything so that it functions smoothly.
Write to the manufacturer with a few words about the short life of the device, which is not cheap after all, and maybe there will be a replacement device.

Your batteries last 2 years?
For us it's just 2 months. Crass.
I also have to mention that we don't have the SureFeed in the flat, but in the closed, unheated tenn.