Using my Tenants Internet Service

[Samantha Cash]

I just closed on a house hack and my tenant who has lived in the property for 2 years has previously split the internet bill with the other occupant in the duplex. I would like to do the same. 

I'm thinking there must be a reason to keep her incoming rent separate from what I pay her for internet, but it would be easier if I could take it off of her rent. Does anyone know of any tax or legal reason why I should keep them seperate?