I'm a Swagbucks user and use Iron source's offer wall to earn bonus SB via the Swabucks live app. I had an offer completion issue, it was regarding a app usage time and I had achieved it, but the offer was still pending despite that. I sent it my query with evidence and it was resolved within the hour. I'm 100% satisfied with their support.
Tip for consumers: It's safe to use and usually rewards instantly, but sometimes there are slight issues with the offer tracking. If you run into issues I recommended you reread the offer terms and made sure you completed them, wait 48 hours. If it's still then contact support.
Sidenote: While Iron source is safe, it's best to research their offer partners before giving them access to your info. I recommend using a secondary email you can dispose of it if the spam gets too bad.