I can’t change my location

Hi guys, i would like to change my location because Serbia has been added to supported countries, but I have 0.3 dollars on my apple id account, I know that i have to contact apple support but its impossible, they don’t have a phone number for Serbia and numbers for Croatia and UK don’t work. Apple support site for non supported countries is endless loop if your problem isn’t listed.

Also I can’t add credit card and then purchase something because all my credit cards are from Serbia.