Manchester City chiefs are convinced Barcelona tried to low ball them in attempts to sign Eric Garcia over the summer.
Off contract in June, Garcia was eager to return to his former club before the market shut this month.
Mundo Deportivo says City were seeking €20m to sell the defender, but Barca's final offer fell short.
The Catalans chose to bid €10m up front, with a further €8m due in bonuses, which was promptly rejected by City.
City boss Pep Guardiola, after their Champions League win over Porto, declared he still had hopes of convincing Garcia to sign a new deal.