How can a Buyer claim Chargeback for unauthorized transaction.

Buyer has left feedback Stating THANK U so they received item? (special list)

Australia Post Tracking number states item delivered.

This is Paypals response via email.

Case Closed

• We weren't able to verify the shipment information you provided. 
• in addition, a chargeback fee of has been debited from your PayPal account

I then phoned Paypal, there responds was Sorry no tracking information for number provided, I then gave the operator  tracking number direct from Australian Post website which clearly states item delivered on 15th May she says yes that's number we have on file but would not recheck tracking info. abruptly replies Case Closed, then asks Can I help you with anything else Today. what a load of **bleep**

I then Phone buyer and ask about chargeback there response was Sorry Husband did not like me using his card?????

This was for a transaction less than $40.00

What next  do we just give away our items instead of selling them as buyers will get them for free anyway with eBay & Paypals policies

Will try and ring again Tomorrow.