The Western Union Company Money Transfers Complaint

The Western Union Company Money transfers department,

International money transfer Wrong amount charged or received Arizona

I transferred $500.00 by Western Union to a relative in -. WU used a conversion rate of $1.00 USD = $1.00 -. I thought that might be a little low and when I questioned the - Phone Customer Service representative he indicaated he understood the conversion rates are determined by the prior days rates. When I checked the currency trading charts I found the rate when I actually transferred the money was $1.00 -. When I reviewed rate history, the last time the exchange rate was in the $1.00 - range was on - - - when the rate was $1.00 -, and the highest rate this year was on -/-/- and the rate was $1.00 -. Looks like I lost $32.00 in the exchange at the lower rate, almost as much as the $37.00 TRANSFER FEE. Should this have cost $74.00 total? How are companies allowed to decide what the exchange rates should be?