Errors: To add products to the Collection by Api

I really seriusly problem with the apis of collection. I'm tries send of excel (xls) by the interface of developer (https://developers.vtex.com/vtex-developer-docs/reference/collection-beta#post-addproductsbyimportfile) but the only result that response the api is "Message":"There is no file in this request." without the cause or context.

Too, I tries the "dowload" the xls or png, i dont know because it doesn't say nothing of result return, in (https://developers.vtex.com/vtex-developer-docs/reference/collection-beta#get-importfileexample) and the result are text with weird values by example ("PK /?jR?H??") and the convert of values of base 64 have error of "base 64 dont valid because contains a caracter that dont is of base64", then how is?...

What is the format of xls for to sended the skus in the collection?

Exist another documentation?

What is the Encoding of result of api of Import Collection file example)

add_002add_001

Hi, I have a same problem. Any solution?
“Message”:“There is no file in this request.”

From Catalog <!-- --> API it does not work test method. It doesn’t work from postman either.