Credit Card Pre-authorization and Guest's Misunderstanding

The main problem we usually face when we pre-authorize the booking value from guest's credit card is that some guest keep insisting that the hotel already charged their card. Every time, we have to hardly explain about credit card pre-authorization to the guest, especially who can't speak english well

This may cause bad experience on guest and inconvinience cause for the guests. 

Could anyone kindly share how you usually handle this kind of situation if you have same experience.

Thank you.