When we were in XXXX, a vendor accidentally XXXX billed a charge of XXXX XXXX, They issued a credit the same date, XXXX/XXXX/15. 
Unfortunately the XXXX charges ( same day ) were billed at different exchange rates and were billed US {$23.00} and US {$22.00}, but the credit ( same day ) was for US {$22.00}. 
When I questioned Citibank they were unable to assist me and explain how XXXX transactions were for different amounts on the same day, they told me to refer to XXXX XXXX XXXX. Does the XXXX XXXX XXXX exchange rate vary by minute? This appears fishy to me. 
