Arrived on site and customer stated that her landlord used a handyman to install a Liftmaster 8500 unit in April 2019. When handyman installed, they did not install cable tension monitor properly causing door to jump cables. Found after inspection tension monitor installed behind motor unit, no vault release installed and fray in cable. Reset cables on door and found spring fatigued and cables become slack at top of opening and opened cable tension monitor switch broken. Customer agreed to new springs, vault release and cable tension monitor. Installed vault release and customer stated that it’s too difficult to pull and would not pay for part even though it does bring operator to manual release. Discounted part as courtesy to customer. Installed all other parts, lubricated and tightened all necessary hardware and door /operator running optimally.