Lazio president Claudio Lotito has expressed his frustration as talks over a deal to sign Felipe Anderson are held up by an investment firm that owns part of his registration.
The Serie A club have held a long-standing interest in the Santos star and he agreed a deal to sign for them back in January.
However, the move eventually collapsed when the paperwork from Brazil arrived after the transfer deadline.
The Biancocelesti are keen to revive the move this summer but talks are being held up by UK-based investment fund Doyen Sports, which owns 50% of the player's registration.
Lotito says an agreement has been reached between Lazio and Santos but he will not bow to what he feels are unreasonable terms being offered by Doyen Sports.
"Anderson is a good player and should we be able to sign him, we will see him soon," Lotito told Radio Radio. "But we won't be conditioned by an attitude of extortion.
"The guy wants to come to Lazio, the clubs agree, but whoever has a percentage of his ownership is using it as a blackmail and I don't agree."