Rafael3206,
Unfortunately, any issues you have with an advertiser must be taken up with that advertiser, as your account with them is private. We have no access or ability to act on behalf of any advertiser. There is simply nothing we can do for your situation.
Our apologies for the inconvenience. We strongly suggest reading the offer terms very closely in the future before signing up.
As for getting credit for that offer, unfortunately, the advertisers do not allow us to request manual credit for offers which pay out less than $7. There is simply nothing we can do to obtain credit for your completion. We're very sorry for the failure to credit.
You can read more about the offer crediting process on the offer crediting FAQ:
http://www.fusioncash.net/faq.php?crediting