IOS TEL Excessive phone charge San Antonio Texas

 May 9 - 12 my wife and I camped at Twin Lakes State Park, outside Farmville Va. There is no cell phone service due to the size of the park. I needed to talk to my granddaughter who was graduation from Longwood Univ in Farmville. Seeing a pay phone near the park office , I tried to call from there. The call was 60 cents. However the phone wouldn't accept coins, so I used a credit card. The call wasn't answered. I was surprised when I received my credit card statement that I was charged $ 23.93. Especially since the call never went thru. I called their customer service and was informed that the call lasted 3 minutes. How? It wasn't answered. The customer service rep imediately gave me a refund of $7.17. but wouldn't cancel the charge. I know Texas law is very loose on these matters, however a markup of $23.63 is way over the top.