If you remove the shift lever by removing the mounting bolts in the base, the entire lever/base should lift right off of the tunnel. Do this slowly and look at the ball on the bottom of the shift lever (the part that fits into the cup of the horizontal shift rod).
There should be a small round pin sticking out of the side of that ball at the bottom and that pin, if it’s there, fits into a corresponding slot in the cup at the front end of the shift rod. Once engaged and the shift lever replaced, that pin prevents the shift lever from spinning around and keeps your shift pattern always in the right orientation.
I suspect that somehow, that pin on your shift lever has either sheared off or, most likely if it is an original VW lever from a donor car, fallen out and down to the bottom of the central tunnel.
So……. you could put a magnet down through the shifter hole and fish around a bit to see if it picks up the wayward pin so you can replace it. If you don’t find it that way, you can do one of two things; (1.) you could try to find a replacement pin at a local hardware store. It should be a solid metal pin and be a force fit, meaning you have to tap it in with a small hammer. After it’s in I would peen around the pin (two sides) with a pointed cold chisel to crimp the pin in place, but tapping it in forcefully with a hammer should be enough to keep it in place.
or (2.) you could simply replace the shift lever entirely and be done with it.