Arrived on site. Went inside store and let staff know on site for quarterly filter change. Set up extension ladder on front of building for roof access. Removed power from both RTUs and changed filters. Noticed RTU2 not running on arrival due to being down since previous visit. Found system void of refrigerant and off on low pressure safety due to leaking evaporator coil. Will resubmit all pending repair quotes. Added dates to all new filters with before and after pictures.