Answer:
The church has always vehemently denied any hand in the conspiracy involving their priests in the corruption cases which vexed the whole congregation but was greeted with derision from the other people who were accusing them.
Explanation:
In one part of the sentence, the party (church) is in complete denial of being accused of doing something. It "vehemently denied any hand in the conspiracy" meaning it completely and strongly refused to accept the accusation. This accusation also led to the angry, annoyed, and frustrated feeling from its supporters.
On the other hand, the accusers react in a mocking way, reacting to the church's denial in a contemptuous and ridiculing manner.
Thus, the sentence presents two ideas where the words "vexed, vehemently and derision" are used.