If the reality is as you have mentioned,
charging an interest of 2% in case of default on payment of the due installment falls under Riba (usury/interest) which is prohibited according to the Qur'an, Sunnah and consensus of scholars. Accordingly, it is impermissible for the Arab Car Agency to take it. Thus, such a usurious transaction is prohibited and illegal. Allah (Exalted be He) said:
...whereas Allâh has permitted trading and forbidden Ribâ (usury).
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.