If there is a difference between map and actual location.

Looking for a specific house on Old School Road, Alloa, Caledon, Peel Region, Ontario, Canada I discovered approx. 600 m difference between the actual location and the coordinates on the map. I simply added the correct address to the map. But, now there are two places with the same address. What is a proper way to fix such mistakes?
BTW, Google map shows correctly all buildings on this street. Just because Google has “Street view” of this area. Is it possible to somehow apply Google map data?

Just don’t copy Google, or any copyrighted map data. Isn’t it stated twice or so before you begin editing?

The error probably exists because in much of Canada house numbers are mapped by interpolation. End points of a line have their house numbers specified and odd/even/both numbers between them will be calculated as spaced equally on the length of line. It may be that this failed due to a sizeable gap in the built up area, therefore breaking the assumption that house numbers are spaced equally.
The best way to fix it quickly would be to split this address interpolation into smaller parts along gaps.
Edit-but-not-really-edit: I see there are barely any buildings on that street. So mapping them individually and then deleting corresponding addr:interpolation would be more sensible.

I think your best bet would be to talk at users: Canada forum here. They will know how to deal with it.

BTW I wouldn’t use the “users: Canada” sub-forum here, because no-one else does. Canadian users are mostly at https://lists.openstreetmap.org/listinfo/talk-ca .