They should be obligated to pay any and all fees and costs, as agreed in the original lease. Whether occupied or not, they have contractual obligations. This normally includes CAM, NNN, etc. The Landlord doesn't even have to re-lease the space to a prospective Tenant to offset any potential losses incurred by the existing Tenant vacating or abandoning the space. Please consult with an attorney for any and all legal advise, as I'm not an attorney. Good luck!
Francis X. Lennarz RE/MAX of Valencia Commercial (661)406-4682 firstname.lastname@example.org
CA BRE# 01010145
Feb 1, 2016