If the contractile vacuole stops working, the cell will die due to the accumulation of excess water and harmful substances. Here's what happens in the cell:

1. Water Accumulation: The primary function of the contractile vacuole is to remove excess water from the cell, maintaining the proper water balance. Without a functional contractile vacuole, water will continue to enter the cell through osmosis, causing it to swell and become turgid.

2. Dilution of Cell Contents: As water accumulates, the concentration of essential substances within the cell, such as proteins, enzymes, and other solutes, becomes diluted. This dilution disrupts the normal cellular environment and impairs various cellular processes.

3. Organelle Dysfunction: The swelling and dilution of the cell can lead to the malfunction of organelles, including mitochondria, ribosomes, and the endoplasmic reticulum. These organelles are responsible for vital cellular functions such as energy production, protein synthesis, and lipid metabolism. Their disruption further compromises cell viability.

4. Loss of Cell Shape: The structural integrity of the cell is compromised as it becomes increasingly turgid and may even lose its shape entirely. This loss of shape affects cellular processes that rely on specific cellular architecture, such as cell division and movement.

5. Membrane Rupture: In extreme cases, the excessive water buildup can cause the cell membrane to rupture, leading to the release of cell contents and cell death.

Therefore, the proper functioning of the contractile vacuole is essential for maintaining cellular homeostasis, preventing cell swelling and dilution, and ensuring the survival of the organism.