Accidentaly selected Multiple entry VISA instead of Single entry

Dear Sir/Madam,

I just applied for two visa through your website (application #EVS439781).
By mistake I selected I wanted two MULTIPLE entry VISAs, but I just need two SINGLE entry one.

Would be possible to change it for both of them?
I am not interested in getting the money back from you but I simply want to avoid paying 50USD when I get to Vietnam instead of 25USD for the single entry VISA.

Please let me know if this change would be possible,

Thanks and bests regards,
Giulia