not sure if you registered with Power supply with your name, if it is, u will get bad record from power supply if you 拖欠水电费.
one more thing, the lady landlord should have the tel no. of him who 经手租约和押金手续, communicate with him if he is the person who signed on the contract. ask for a written letter to state that he will return deposit to you or can use deposit as rental, etc... whatever that you can get his agreement and her agreement.
by the way, 用押金抵最后一个月租金,这 IS our 惯例. so am thinging that maybe other people can also accept?