You need to contact the theme developer and try to negotiate a refund.  Depending on how long it has been since the purchase and if you paid via paypal, you may be able to get some assistance from paypal on the matter. 

If none of that works and you feel unsatisfied with the outcome or the support of the developer in any way, you can send a message to the moderation team at moderation_team@oxwall.org to let them know your concerns.  Then leave a review of the theme so that others know your experience.

Oxwall does not have any control over how the developers run their business however if the developer is not offering a valid product then Oxwall does have means to deal with those issues.  But Oxwall does not give refunds itself or negotiate refunds for store customers.  

I stand corrected, i did have that in the wrong order.  Thanks OW for pointing that out, you are correct.  :)

I have corrected my post. :)  I put the cart before the horse on that one didnt i  :)