Please contact Samsung Account Support Team to ask them to change the country applied to your Samsung Account.
You can follow this link help.content.samsung.com log into with your Samsung Account, (change the country/language at the bottom of the page if you want) select Samsung Account, 1:1 Enquiry and ask them for the changement.
See you soon!
Un assistente vocale per il tuo ecosistema Galaxy: Bixby