Unfortunately, you should have accepted the refund.
...its description that it was 24 carat gold plated.
You know that gold plating is always 24 karat, right? But that is a layer about as thick as the lipstick blotted on a tissue. We're talking drugstore jewelry here.
Now.
To get a refund through eBay or Paypal, you must file the complaint within 45 days of the original purchase.
The 'replacement' scam is relatively new, but has the advantage that whether something is sent or not, the PP deadline will have passed by the time the sucker customer realizes she has been taken.
Then, you have to return the item with Delivery Confirmation* (and if this was, as I suspect, a Chinese seller, that would cost over $40).
Without proof of delivery, Paypal will not process a refund.
You might try calling the 1-800 customer service number for the credit card you actually paid from. (PP just mediates the payment). Cards tend to have longer (60 to 90 day) deadlines.
* BTW, PP does not accept Registered Mail (about $12.50 for overseas) as proof of delivery. You must use Expedited or ExpressPost which is much more expensive.