Rule reminder
A formal complaint letter (lettera di reclamo) follows this structure: (1) Object/Oggetto, (2) Opening formula referring to prior contact, (3) Description of the problem using formal vocabulary, (4) What was expected vs what occurred, (5) Specific request for remedy, (6) Deadline or consequences, (7) Formal closing. Each section has standard formulas.
In a formal complaint, how should you refer to a phone call you made previously?