You have also wrongly accused the organisers of spending too much money on organising the event.

wrongly 是形容词 wrong（错误的）加上副词后缀 -ly 构成的副词，表示"错误地"。 accused 是动词 accuse 的过去分词形式，accuse 的意思是"指责、控告"，这里表示"指控"的动作已经发生。