Pfc. Manning was serving with the U.S. Army when he was arrested and charged with the unauthorized release of confidential information.
Jeff Patterson of the Bradley Manning Support Network told The Sunday Telegraph of London, "From July, WikiLeaks publicly solicited donations specifically for Bradley's defense expenses, and I assume people did donate.
"They led us to believe they would make a substantial contribution in September. Since then we have had perhaps half a dozen conversations trying to follow up with them but we have not yet received any money."
Manning was arrested in June on suspicion of leaking military logs from the Iraq and Afghan wars.
Meanwhile, a senior WikiLeaks activist, Icelandic parliamentarian Birgitta Jonsdottir, told the Telegraph she and others have quit the group in grave concern about its treatment of sources and "lack of transparency with relation to large sums of money."
The paper also reports that a major WikiLeaks funding channel, the Wau Holland Foundation, has been been twice officially warned by German charity regulators for failing to file financial records.
PayPal, which last week cut off donations to WikiLeaks, has suspended the site's account twice before, once under money-laundering regulations.