I cannot open the door for my gas tank filler. How do I get this open?

Have someone pull the lever inside the van while someone else pulls on the door. Hopefully it will open and you can see what's going on with lever/release.

Good advice. The problem is due to a broken actuator spring. Replacement springs are available (I bought a handful from OlathToyota.com). When you install the replacement spring be sure to remove the broken base of the old one and note where it is so you install the new spring properly.