Sign with certificate (Spanish FNMT, Polish ProfilZaufany...)

 I work in Teams and we recently had to sign 5 of us a PDF with Spanish FNMT certificate. Three of us Windows and Adobe Reader DC, fourth with Ubuntu and Spanish AutoFirma. The fifth had Linux and couldn't install any of above software. I sent him a document with four signatures through Adobe Sign email. The document came back with four signatures deleted (no trace of verified four signatures in signature panel, only icons in the text) and a digital signature of Mr Adobe Sign in signature panel, not with the name of fifth person. No icon of the name. The final document was useless. Did I do something wrong, or Adobe Sign puts company name instead of the person who signs it?