I really get wary of credit card uses in Mexico. I just spent 2 months trying to get $600 for a customer on the caravan I led in Spring. They put 2000 pesos worth of fuel in their motorhome in los Mochis. The bill came through as 8000 pesos. Coincidentally there was a 2000 peso charge on their card for a station in Navajoa for the same day & time, where we did not stop. Impossible without a warp drive. It took awhile but I found out that both stations were owned by the same company. That smacked as some sort of computer error to me. They had a heck of a time until they managed to find the receipt for los mochis showing 2000 pesons. At that point the credit card company relented & refunded. Heck that is what those 18% interest rates are for.
Moral of the story is always make sure you get a credit card recieot and never throw it away.