Good morning @fpcampomanes and welcome to ODK Community. Take some time to introduce yourself here
I do not know if it is the reason of your problem but I never used this select_one_from_file syntax to query a media file and it is not in the question types documentation page : https://docs.opendatakit.org/form-question-types/
Here is your form with the syntax I use.
I "bolded" the new lines (survey and choices sheets)
On the survey side you define your select_one and appearance mention the csv to query
on the choices site, for both products and brand list you define the name and value column used in the media files.
Hope it helps.
DuFry_sales.xlsx (9.9 KB)