X. If an action initiated under RSA 540-A:3 is found to be frivolous or brought solely for harassment, the plaintiff shall pay to the defendant the costs of said action including reasonable attorney's fees. If such frivolous action was brought by the tenant, he shall not be entitled to the protection of paragraph XI of this section.
XI. No action for possession may be maintained by the landlord against a tenant who proves a violation of RSA 540-A:3 except for nonpayment of rent, violation of a substantial obligation of the rental agreement or lease, or violation of this subdivision within 6 months of an action instituted under this subdivision by a tenant; nor shall the landlord take any other action in reprisal.
XII. Relinquishment of possession or abandonment of possession shall be an affirmative defense to an action brought pursuant to this chapter.
(a) Relinquishment of possession occurs when the landlord receives a statement signed by each adult tenant of a rented or leased premises stating that the tenant has relinquished possession of the rented or leased premises and has no intent to return.
(b) Abandonment of possession means all tenants have physically vacated the premises without the intent to return. There shall be a rebuttable presumption that the tenants have abandoned the premises if:
(1) The landlord provided all tenants with a written property abandonment notice, by leaving the notice at the rented or leased premises and by sending the notice by certified mail to the last known address of at least one adult tenant. The property abandonment notice shall also comply with subparagraph (d); and
(2) At least 2 of the following conditions were present: