To the OP it actually is possible to keep a plant cutting alive in water like you have it. Change the water out with fresh every couple of days. The way you know it’s working is the stem in the water will begin putting out roots. If you don’t start getting roots then the cutting has died an at that I point I’d just hang what you have left an let it dry.
Also you need to find a more secure site to grow. Whoever ripped you off knows your set up an no doubt will hit you again in the future.