This is "Do you exist, Mr. Jones?" (alternatively translated as "Are you there, Mr. Jones?") by Stanisław Lem:
* The protagonist, Harry Jones, is an auto racer.
* During his career, he had suffered multiple injuries and had all of his organs, including his brain, replaced by luxury prostheses.
* His brain, manufactured under the brand name "Geniac", is a repurposed tabulator, which makes loud noises when Jones is thinking hard.
* The prostheses were financed and he had defaulted on the loan.
* The manufacturer or the prostheses, the company named "Cybernetics, Co.", is seeking to repossess the prostheses in the court of law.
> The court is unable to make a decision, because it is unclear whether Mr. Jones is a natural person (who cannot be repossessed) or property (that cannot be sued)
This story discusses the question of personal identity (similar to Theseus's Ship or Grandfather's Axe, but in humans).