[mdcds]

Since said person doesn't want to listen you and you don't have the direct authority over that person, I think it's reasonable to ask the team manager to deal with it.

Say something like the following. Just remember to include specific pieces of evidence that support your claim.

"Person X doesn't seem to care about company policies regarding the code quality. On following occasions: <list of offenses by person X> he/she did something sloppy that was against the policy A and refused to even acknowledge it during the review. Can you explain him/her why following these policies is important"