what to do with lodgers?.......

[katrin]

For the last several months I have been renting out several rooms to lodgers. They are three young guys and all of them study at the University, they pay their rent, and I find them very nice to chat. I like they always pay their rent in time.But several weeks later I began to have problems with noise, especially when they have a party on weekend, sometimes they used to play music loud in their rooms.A week ago when my lodgers had a party I managed to fall asleep but my neighbour did not. He came to me and complained of my lodgers. Of course I was confused with these guys behaviour and do not have any idea how to deal with them?