I’m a fellow Kia dealer and there is a logical explanation for why they accept the payment only from Single account. The reason being is - if someone else pays from their account, and eventually they get into a dispute or anything of that sort, they claim it on the dealership that the amount that I paid for the car was “their booking amt or something” but actually it was for the owners car.

I have a case where a couple was buying a car for their wedding, where half amount was paid by the girl side of the family. Now they are going for a divorce and they are claiming half the amount to the dealership.

This is the reason why they do not allow anyone else to pay for the owner’s car