Poor rental service

Poor service We rent a intercom system at Nashua Vaal We report it in January to fix the intercom In the beginning of February we have a meeting with Nashua Vaal about the intercom not working They send out a technician to fix it but it is still not working We report it and have a meeting with Nashua but no progress Why must we pay the rent if the intercom is not working and they dont fix it or replace it Then I can stop the contract