Customer refunded via A-Z but the return has been lost

Is there an Amazon Representative here that can help me

Customer opened a return for an order that was no longer required. Amazon issued label and the return never arrived. customer opened an A-Z stating "Different from what I ordered" to get a refund. this was granted and I opened a help case and it was stated that the refund was not funded by me. A few days later I get a new email stating decision made on A-Z refunding the customer from our funds and has impacted ODR. Return never arrived. I spoke to customer service who were useless and said to appeal the A-Z with the return tracking showing its got lost and hey presto they have upheld the decision.