Since the system has more disadvantages than advantages, I disapprove of [the] "open 24 hours a day, seven days a week" system.

disapprove 由前缀 dis-（表示"否定"）和 approve（"赞成"）组成，意思是"不赞成、反对"。 the 是定冠词，在这里特指"每周七天、每天24小时开放"这一具体系统。