A320ECAM
...I would maintain (or even climb to a higher) altitude and await further instructions.
You have two energy sources; #1 fuel in tanks, and #2 (a portion of) fuel already burned. You need to take the airplane to the highest possible energy state so when #1 is gone, you have the best possible remaining energy.
And in a critical state, I would remind ATC that they do NOT fly the airplane, and would announce that I am landing ETA...