Refunds - variance in amounts

[Pixart]

I was hit with two refund emails from DT, both for $6.24 - same subject, different composition.   $12.48 is a pretty significant amount for DT so I combed through my sold files and have never sold a photo for this amount.   There isn't a single sale for either photo in this exact amount.

Either (a) they made a mistake (I don't really expect DT to make mistakes, they seem to have their act together)
or (b) they are subjecting me to currency fluctuations. 

If they PAID me in $U.S. I don't really give a crap what the customer paid or was refunded in - am I not realistic in expecting them to debit me exactly what they paid me? 

Or else do they possibly remove the sale from the list once it has been refunded = resulting in me not being able to find the sale?

Thanks!

[heywoody]

Possibly both transactions happened very close together and you never noticed the relevant sale - i don't think refunds show on sales history () so, logically, the sale would have to come out to keep the total correct.