Credit for charge in April

I placed order # 4322 on 5/17, but another order in April I placed was not completed or did not go through. The credit card I used has been charged twice, but only 1 order was completed.

I need to know what process I need to go through with getting the credit card used credited for the additional charge.

Please feel free to give me a call at 315 699 0098 or 315 727 1379

David