Front Camera has a green screen color bug

Hello, im from Ukraine, Kiev, unfortunately we don’t have an Apple store in my country, so 15 of november i’ve purchased a new iphone 11 pro max in an apple store in Rome....

when i’ve back to Ukraine i’ve figured out that the front camera of my iphone doesn’t work properly for taking both photos and videos... it gives me a green screen/image every time i use it...so im literally not able to use...

I wonder how can i change my phone ? if it’s possible to do in any apple store of any country ? also how many days after the purchase i have to exchange it? if it’s possible to do somewhere in Ukraine?