Can't get in Reverse

The hole for centering the shifter is kinda hidden. There is a notch on the bottom of the shifter body. Its kinda hard to see it in the picture because its grey/brown color. Here is a pic of its location. It sounds like the shifter is still in another gear. Also lubricate the shifter and its sliding plates with WD40 to loosen up the grease in it. Ideally you should take the shifter apart to clean out the old grease and put in new grease.