Harassment by Tenants

10 days back 2 persons visited our house, and asked our house for rent... We informed about our terms before and he agreed on that day and have given 2 months of advance which is 10K... This Monday they shifted to our house. The most important term which we mentioned is usage of Water and how much time they should switch on Motor per day (20 to 25 mins once in the morning, and if emergency 10 more minutes in the evening). Everyday they cross across 30 minutes of motor. On Friday, in the morning they used motor for 15 mins, and 20 mins twice and in the afternoon they switched on motor again, and when asked why using the motor multiple time, the lady overragged on me saying that we are paying 5K,we will do whatever we want and use how much water we want n use motor how many times we want. And then they left the motor overflowing. I had to inform them to switch off the motor again n again. When asked what is this kind of behavior? The tenant is saying "Why all this? Give us our advance 10K and the luggage shifting charges which is 10K, but we will not pay a single penny for the 20 days stay and not even pay for current bill also". What should we do now? Please advise on how this can be dealt??