Turtlemarine.com Limited Charged me twice so I paid extra tax at my end then credited my account at much less exchange rate Shelton, Connecticut

Turtlemarine charged me NZ$835.21 for a 747c humminbird fishfinder, cable and cover. They also charged my credit card NZ$641.67 at the same time, what for I do not know.

I emailed them asking what is going on and they did not respond until the product left the US and i was then charged New Zealand GST (goods and service tax) of 12.5% on the total amount. This was payable to UPS as they had already paid this to Customs for me.

I am out of pocket NZ $39 here plus when they credited my credit card several days later I received NZ$555.00 instead of the original NZ$641. Now I am NZ$125 total out of pocket! and not happy. I emailed them and said the difference in their exchange rate was 18% and their was very little change in the International rate at this time.
I asked them to help me to retreive this money, they said they did not understand the numbers I was showing them. I gave them more info but got no reply back.

David
dunedin
New Zealand