Being asked for what you already hold
Nothing signals indifference faster than a question you should already know the answer to.
There is a particular irritation in being asked for information you have already provided. It is not merely inconvenient. It carries a message: the organisation was not paying attention, or its parts do not speak, or the record of you exists but nobody bothered to look. The customer draws a reasonable conclusion, which is that their time is worth less than the cost of joining two systems together. They are usually correct, and they are being told so directly.
The same insult arrives in slower forms. Being asked to post a document that was uploaded last month. Being asked to confirm an address that appears on the letter you were sent. Being asked to explain a history that is sitting on the screen in front of the person asking. In each case the organisation holds the answer and has decided, through inaction rather than intent, that retrieving it is your job.
Some of this is genuinely hard, because old systems do not merge cheaply. But much of it is procedural habit that survives because nobody has questioned it. Start by listing every question you ask and marking the ones you could answer yourself. Where the data exists but is not accessible to the person asking, that is a plumbing problem worth costing honestly, because the current arrangement is not free. You are simply paying for it in customer time, which never appears on your budget.