Originally posted by FAQ:

4. I finished earning credits and it didn't pay me!

Credits earned through completing offers are not managed by us. If you didn't get anything, neither did we. Make sure an offer has been fully completed per our partner's instructions, and that the offer was valid for your area. Our ad partners do a good job of correctly processing credits.

Page 1, 2, and 3, all have ways to contact the company if you did not receive credits for an offer. It is located on the /earn page near the top-right. Check on the page under 'Support' or 'My Credits'

A customer recently contacted support for one of the offer sites and received a list of reasons accounts may not receive credit.[gyazo.com]