How do I report a problem with some ads not awarding tokens?

I normally use a web browser to log on to topeleven.com and click on the "Watch The Video And Earn Tokens" link to earn some tokens. There are a few ads that repeat everyday but do not seem to award tokens.

I am aware that you're supposed to contact the offer provider directly to check what happened if we don't receive our rewards, but I don't know who the offer providers are as that link takes me directly to the ads.

My question is: what is the correct procedure to report a problem with these ads in particular?

Many thanks.