False A-Z resulting in ODR and refund

We have had a customer put an A-Z in for an undelivered item reason below:

'Package didn't arrive' and customer comments;

'Customer comments: Is anything missing? Yes. What's missing? The entire package or received empty package. Did your address change? No. Reason Code: NOT_RECEIVED'

The item has been delivered with the POD image and the customer signature, this info was sent to the customer and they said they never sent for an A-Z claim and called us liars etc etc..

Sent a screenshot of the A-Z claim that was submitted with 'customer comments' and again they said they never did this, I explained to them that this was unlikely as it is usually triggered by a buyer contacting Amazon, however I can understand how the use of Amazon and contacting sellers via the messaging centre can be confusing etc..

They eventually agree to contact Amazon to remove the A-Z claim, which after about 24hrs it was.

Then this morning we have had an email saying;

'Your account has been debited the original shipping amount for order 206-1557330-1374740. This is because you did not refund the buyer for those costs.

As the buyer returned the item you are required to refund the original shipping costs'

Firstly, we are only required to refund shipping costs if the item is faulty and returned, of which the appliance is NOT faulty, and has NOT been returned?!?!'

Why have we been charged for the shipping costs we have passed on from the courier to transport a 55kg box over 1.5m long over water to the customers house, for no apparent reason or proof.

@Sarah_Amzn@Roberto_Amazon@Winston_Amazon