Sounds like the voltage divider has the wrong values. Use a mulit-meter to check the output from the network, you should either get close to 5vdc, but not higher and very close to zero, depending on whether it's normally closed or normally open. You also need the pull-up resisters enabled.
Another way to use a proximity sensor is to have it operate a 12vdc relay. I used a [
www.amazon.com], and used the relay output as the switch. I used that one since it didn't need to use a slow boat from China to get to me and you could select that it triggered on high or low signal. No resisters needed with the relay. The extremely short delay in operating the relay hasn't affected the use of the sensor's reliability.