Adsense is deleting my earnings in day

Dear friends ,
I have problem with my account for 2 weeks.
In a day my earnings are always reduced . I dont why .
For ex. today my earnings was 100$ but after 1-2 hour I saw that it is reduced to $60.
It is like that for two weeks , I dont know the reason. I dont think it is about invalid clicks ,everyday $30-40 is a huge amount. There was nothing same before .
How can I solve this problem ?
Thanks in advance.

See original post by Johnalvarez