SFP Amazon customer services issued a partial refund

Last week a customer opened a return request on an item that was sent using SFP which was auto accepted by Amazon. They stated the item was faulty which of course would mean he would get a free returns label (due to the item he had purchased I can confidently state with 99.9% certainty that it was not faulty) Then the next day I get an email saying that the item which cost £38 had been issued a £7.00 refund. Now if the item was indeed faulty why would the customer want a partial refund? So I open a Safe-T claim to be reimbursed this amount as we will issue a full refund when the item is returned. Today we got the following message:

_"Hello, _
_ _
_We have denied your refund request for order xxx-xxxxxxx-xxxxxxx because a full refund has not been issued to the buyer. _

You can find more information about the Seller Fulfilled Prime program terms and reimbursement policy here:"

So basically it would appear that they could have received up to £37.99 as a partial refund and we would have no leg to stand on. Looking at the policies stated it does say that they may at their discretion offer a partial refund but it doesn’t state that these are non appealable. I guess we will have to chalk it up to one of those things unless anyone knows otherwise.