Amazon Is Repeatedly Giving Invalid Return Codes

The website refuses to accept returns, repeatedly providing invalid return codes, making it impossible for me to return the product. Both DHL and MNG consistently provide incorrect consignment return numbers, when I contact customer service they give assurances of a resolution "soon," yet the issue persists without any actual correction. The continuous runaround between Amazon and the courier services has left me in a state of helplessness, unable to return the item as intended. What a sor experience to say the least!!