On Tuesday, Messi and his representatives sent a 'barofax' communicating his desire to leave the club, with that type of fax requiring an acknowledgement of receipt from the letter recipient.
The Argentine is unhappy at Camp Nou after the team's poor performances on the pitch this season, as well as the unclear direction at board level.
Things came to a head after Barcelona were knocked out of the Champions League after an 8-2 demolition from Bayern, which resulted in head coach Quique Setien being sacked and replaced by Ronald Koeman.
Following the elimination from the Champions League, rumours circulated that Messi was looking to move on, with Koeman immediately seeking a meeting with the club captain after his appointment.
Now, under fire president Bartomeu, who has continually said that Messi will finish his career with the club, is desperately attempting to call a face-to-face meeting with the player, according to Catalunya Radio.