I thought "прошу" was the response to "дякую", and "будь ласка" is for when you make a request. Or is it wrong?
Прошу is only a response, "будь ласка" can be used both ways
I am not sure why "прошу" is not accepted here. "прошу" is like 'bitte' in German - meaning please. "будь ласка" - means something like 'let there be the kindness' (similar to when you use 'ласкаво просимо').
Будь ласка also means "please", right?
What is wrong? Why ???
The correct English translation from Ukrainian would be "thank you". "будь ласка" covers the meanings of two separate and non-interchangeable English terms: "you're welcome" and "(if you) please".