Please tell me what words are untranslated to understand what translations you need to edit.
And provide temporary admin panel access.
By default every WP should have the following translation:
1) WordPress translation files. They should be located in wp-content/languages/ folder, for example, es_ES.po, .mo
2) Plugin translation files. They should be located in wp-content/languages/plugins/ folder, for example, woocommerce-es_ES.po, .mo.
3) Theme translation files. They should be located in wp-content/languages/themes/ folder, for example xstore-es_ES.po, .mo.
If you have translation files in other folders, please, move them into folders that I described above to avoid any problems with translation.
Depending on untranslated words you should edit one or the other translation.