A320 Captain reported nose wheel's uncommanded roll over improper chocks resulted in ground loss of control.

Narrative

After taxiing into gate at ZZZ after operating flight from ZZZ1 to ZZZ we experienced an uncommanded aircraft movement while the airplane was chocked after block in. The event occurred after releasing the parking brake in order to cool the aircraft's brakes in accordance with an ECAM message. After the parking brake was set to on after block in and verifying that the aircraft was chocked; I released the parking brake which resulted in the aircraft slowly moving backward. After realizing that the aircraft was in fact moving rearward and not just rocking into a stopped position against the chocks; I immediately applied the brakes and set the parking brake to on to stop the aircraft. After communicating with the ground crew once the aircraft was stopped; I was informed that the nose wheel of the aircraft had crushed the chocks and rolled on top of them. Fortunately; my prompt response was able to stop the aircraft before the nosewheel continued beyond the crushed chocks which could've resulted in the aircraft impacting ground personnel; the jetbridge; ground equipment or another aircraft. After further investigation; I was notified that incorrect chocks were used to chock the aircraft and that they were not rated for airplane use. A further safety investigation found that the chocks used on the ramp that day were actually meant for ground service equipment and were inadvertently mixed in with other airplane rated chocks which allowed incorrect chocks to be used on our aircraft. After making sure that the aircraft was no longer a threat to having further uncommanded movement; we verified that no person was injured and that no damage had occurred during the event.