Santos have accused Barcelona of creating a "smokescreen" over their failure to pay a €2 million bonus clause after Neymar was named on the Ballon d'Or shortlist.
Barca signed Neymar from Santos in the summer of 2013 in a complicated and controversial deal involving several bonus clauses, which the Brazilian club say included an obligation to pay €2m if Neymar was named as one of the final three Ballon d'Or nominees.
Barca are said to have written a letter, which was leaked to the media, in which they said they will not pay the bonus until the ongoing dispute between the two clubs over the 2013 transfer is resolved.
Santos, who have filed a compensation claim with FIFA over alleged "irregularities" with the transfer, said in a statement on their official website that they did not receive the letter from Barca but believe the Primera Division side are relying on "legal obstacles which in fact do not exist" to avoid making the payment.
The statement said Barca "are just using a smokescreen to try to get out of their contractual obligations" and that it represents "a clear example of breach of contract."
Santos said they would issue an "appropriate response" once the correspondence from Barca was officially received and warned they would take whatever measures necessary to claim the money they feel is due to them.