In Wannads Offerwall, click on the support button at the top right, and you will be displayed a list of tasks you have done; if it has been completed successfully, there will be a contact link. If there is no link, you have not completed the required tasks.
Or you can go to Wannads - App monetisation.
We do not have the information on the offer you made.
We do not have confirmation from their advertiser that the offer was correctly completed.
We host these services for you to earn; we have no control over them.
They need at least 30 days to investigate what happened and to reward you.