Tenant terminating lease early Need advice in NH!

[Jeremy G.]

Hello BP!

I purchased a 3 unit multifamily property in august of this year, it was occupied by 2 tenants and I moved into the 3rd unit, when signing new leases for the existing tenants one of them gave me notice to terminate because he bought a house, good for him! took me a couple weeks to screen and find a new tenant, but I found one with a great co-signer who agreed to pay for all rent and any damages that may occur, AWESOME! signed a month to month lease with the possibility of going long term, this was on the 10th of October. the father paid 996 security deposit, 996 first months rent for November and also paid daily rent from october 10th to the end of october. so overall it was approximately $2500 for his daughter to move in. 

Since the first day she was occupying the unit, its sounded like her children are smashing the floor with a sledge hammer, even at midnight on school nights while my child is sleeping(they live right above me) I have been extremely reasonable and respectful and have only texted her 3 times since october 10th about the noise because it was waking my child up on school nights. come November 3rd I receive a text saying hey we are starting to move out today(the 3rd) and will be out by the end of the week, I said "okay well proper notice would have been appreciated but great! the sooner the better!" "let me know what date you will be out so we can do a walk through and i can get the security deposit back to your father" she and her father both texted me saying they are paid through the end of November and that they expect a refund for the unused rent for November..

My question is, am I obligated to refund them for the unused portion of rent for november? even though they are voluntarily terminating the lease without proper notice? 

Any helps or advice is greatly appreciated!

Thanks 

Jeremy