I’d send over a quick email to Eufy Support at support@eufylife.com and tell them whats happening and tell them what troubleshooting steps you did. They may not respond until next week. They are on holiday so they have limited staff on duty.
If you have not already done so, remove the the clear plastic that protects the body. If you have you already done that then try cleaning the sensors. Also try unplugging the base unit for about a minute, if there’s a power switch on your unit, turn that off as well. Remove the batteries from the remote. Wait about a minute or so and try again. These are a few tricks I have used to get mine working again.
If you got it from Amazon then you have a little bit time before the return windows goes away. Get with support and see what they can do for you if my tips didn’t work. If they can’t get working they will make it right.