If you haven't yet logged in, do that.
Then open the personal profile page of post's author by clicking the link under his nickname.
See the date of his last appearance on the site (see "Дата входа").
If he logged out not long ago, send him a private message with appeal for re-uploading of material and, correspondingly, for updating a link (for start, press to "[ Отправить ЛС ]").
You may also apply for assistance to anybody who posted a thank-you comment.
Please, don't post a request for update a link in comment, because that will have no effect, as a rule.