The vast majority of Readers on these forums are regular users like you. In the English language forums, the majority of those are in the US, happily using using the US keyboard without thinking deeply about other keyboards and languages.
Are you saying the glyphs on the keyboard changed from what you had before? That requires a different physical keyboard.
If instead, only the keyboard translation was changed, that is merely a setting:
system preferences > keyboard > Input sources
You are welcome to contact Apple support, but they will tell you the same advice -- they will not be able to intervene on your behalf.
To get the keyboard changed to the one you used to have, you need to contact the Repair agency you used and ask them to "make it right".