A321 flight crew reported cockpit seat was broken and incorrect bolts were used to install it. Maintenance installed new seat and replaced bolts with correct ones.

Narrative

Aircraft arrived with captain setback adjustment broken. Maintenance personnel began taking apart the seat to try and repair it. It was found that a replacement seat was required. After a long wait the replacement seat arrived but could not be completely installed. Maintenance personnel found that the bolts used to install the removed seat were the incorrect length/size. Therefore we had to wait for replacement bolts to arrive. After receiving the bolts the seat was installed. It is unknown how a Company airlines passenger carrying aircraft could have the wrong bolts holding the captains to the aircraft.Poor company maintenance procedures and inspection procedures during the previous/old captains seat installation. The old captains seat was not properly installed and the aircraft flew many passenger flights with the captains seat not properly secured to the flight deck floor.Company management maintenance procedures should be reviewed to figure out how and where this error could have occurred. FAA and Company maintenance should investigate this issue and make corrections so this type of error does not occur in the future. Company maintenance management should reward the mechanics at ZZZ who did a superb job and found this error.