We have every reason to cancel the contract because you've failed to fulfil your part of it.
我们完全有理由取消合同,因为你们没有完成应遵守的合同内容,履行合同。
because they are unwilling to have their names entered as having taken out such and such a book,
因为它们不愿让人家记下它们公司的名字和借阅的某一本书。