Every reason code wins on the same letter arc.
Most rebuttal letters that lose, lose on structure rather than on evidence. The merchant writing the letter knows what happened, has documents that prove it, and produces three paragraphs of prose explaining the situation. The issuer reads it once, finds no answer to the specific question their structured questionnaire is asking, and rules against the merchant. The evidence existed; the letter just did not present it in a way the issuer was equipped to use.
A defensible letter for any reason code follows the same arc, varying only in the evidence it carries. The opening cites the dispute condition (Visa 13.1, Mastercard 4853, Amex C08) and the rule edition, which signals to the issuer that the merchant knows what they are arguing under. From there, the body presents evidence in the order that addresses the issuer's structured questionnaire, pre-empts the cardholder's most plausible counter-argument with a specific record, and closes with a clean request for reversal under the cited rule.
Repeating the same structure across every letter, while varying only the evidence and the reason-code citation, gives experts substantially higher win rates than letters written freshly each time. The reason is that the issuer's reading is the same every time: structured, time-pressed, hostile to surprise.