If you have not recieved free credits after completing instructions from Offer wall, please wait a little while, It might need time credits to appear on your account.
If that does not help and you are still not seeing added credits please check the images and follow the instructions:
1. Go to the Voxofon app, go to the 'add credit' page, then tap 'free credit' (see attachment 'voxofon credit.png', the area is circled pink)
2. On the offer wall that opens scroll to the bottom of the page, tap the 'missing credit' link (see the 'offerwall.png' attachment, the link is circled pink)
3. On the page that opens find the offer for which the credit is missing, tap the 'missing credit' link there (see the 'pending offer.png' attachment, the link is circled pink). IMPORTANT: if the timeframe for the offer being credit has passed, the 'missing credit' link will appear; otherwise it will only say 'pending' but the link will not be there. In this case you will have to wait a bit and whether the credit or the link will appear.
4. On the page that opens, scroll to the bottom and (if you are sure the offer was completed correctly) tap the link 'submit a support ticket'. (See 'submit ticket.png' attachment, the link is circled pink).