A contact list shows José where you expected José. Correcting every name by hand is tempting, but it may repair the wrong layer. The file's bytes can be intact while the importing application interprets them using a different character encoding.
Keep the downloaded original. In Excel, use the text or CSV import route and inspect the encoding setting and preview. Microsoft documents UTF-8 import options, including files without a byte-order mark. The available controls depend on the Excel edition.
Pick a few diagnostic values: an accented surname, a currency symbol and a non-Latin place name. Check columns and separators as well; a correct accent does not prove that every field landed in the right column.
Do not overwrite the original while the preview is garbled. Import into a new workbook, compare several records with the source and only then save a working copy. If replacement characters were already written into an earlier export, changing the encoding may not recover the lost letters. Ask for a fresh export with its encoding specified.