special offer bug

Hi
This morning i had an issue where i was overcharged for converting synergy.
the offer said 400 per i GS but i was overcharged on my purchase.
Has anyone else had this issue ?

and how can i get this rectified?
thanks  

You should contact the support team here https://support.gaijin.net/hc/en-us/categories/200005051-Star-Conflict