About a year ago I decided to use more than one agency. Until then, I offered my videos only in Pond 5. I started use Videoblocks, Motion Elements, Shutterstock and others. Then my sales in Pond5 dropped. Of the other sites I have almost no sales. What do you think, is there a connection? Think that i will end used the other sites and stay only in Pond.

I also think there is no revelant, but for me this is fact. So I please for yours
  opinion. I really do not see any reason to reduce my sales in Pond5 so much. Did I seem to have mistaken the use of other agencies?

I don't think that Pond5 doing something. Perhaps buyers are confused when see the same clips on different sites and refuse to buy. I strive price in other sites be same of all my videos. Unfortunately,  my sales were down a lot when I started selling on several other sites . Nobody had a similar problem?