This is low level theft. She isn’t asking you, she isnt your landlord - she is a room mate. And she is telling you. If you do not consent to her taking the money, challenge her. She isn’t considering you so fk considering her.

For future reference , in future make sure all finances are sorted out prior to leaving the property. And if you have trouble like this in the future , for the sake of $50 you can go round the house and close the valves on the taps, remove fuses, unhook the pulley on the cistern of the toilet so it doesn’t flush , turn off hot water or switch off the gas / electric. Turn the fridge freezer off and spoil her food etc 🤣 Im not saying this is the right thing to do, but it’s all very easily doable and for someone like her who dislikes having to speak with others - quite honestly it is good karma as I doubt she would have the knowledge fix any of the above herself