The Serie A side's Spanish representative has revealed that the Catalans actually spent more to sign the forward than they revealed on their official website
The Nou Camp outfit stated on their official website at the time that the Chile international cost them an initial €26m (£22.7m) plus €11.5m (£10m) in bonuses.
But Pina insists that Barcelona did not get their man for the transfer fee they publicly announced.
"Alexis cost them €43m. This figure does not match the fee that Barcelona announced on their official website. They claimed that he cost them a set fee of €26m plus €11.5m in bonuses," he was quoted as saying by Deportes Cope.
The 22-year-old attacker signed a five-year contract which will run until the summer of 2016.
He sustained a hamstring injury shortly after making his official debut for Barcelona and is currently working on his recovery.