Files deleted from Microsoft OneDrive are not completely deleted unless the recycle bin is emptied.
To do this :
Access OneDrive and from the lower left corner, click on “Recycle bin”.
The deleted files will be present in recycle bin (this is because if a restoration is needed, it can be done from here).
To permanently delete these files, select them as needed and choose “Empty recycle bin”.
Click “Delete” when the confirmation box pops up.
Wait for the process to finish.