Long-term guest fee Covid-19 (New Hampshire)

[Keith Annis]

Good Afternoon. My tenant is violating the lease having an unauthorized long-term guest. Our lease states a fee for an extra guest, is that fee against to the Covid-19 law? I am new on that landlord thing and this tenant came with the house I bought and according to the former owner (her stepfather) She was a good person but in our first month here, we found out that it was not true. As we know the type of person she is, we put cameras on the driveway to have proof that this other person was living with her. When I delivered the notification about this fee she told me that I would have to prove that this person was there for more than 10 days, and said that in fact this person was only there for 5 days, since this person has been living for more than a month.

What can I do about that?

Ps: I am sorry about my broke English, I am not american but I am trying hard to improve this.