Handling Conflict over the Telephone -
Be especially aware of your tone of voice. More than ever, it needs to be pleasant, concerned, patient, informed and caring. Lower voices are perceived to be more mature, confident and in control.
Listen very carefully so you understand exactly what happened. Often the details can tell you just how deeply the Guest has been offended, and they can give you ideas for what action you need to take next.
Empathize with their feelings, regardless of whether or not you agree. You can still relate to the fact that they are feeling hurt, offended, or wronged in some way.
Propose a plan of action. Offer some next steps that may keep the Guest from having the problem in the future, or will at least let the Guest know that the appropriate people will be notified so it doesn't happen again to anyone else. You could offer some kind of compensation, if it is warranted.
The 3 F's: Feel, Felt, Found-
I understand how you could feel that way. Others have felt that way too, and they found, after an explanation, that guideline made sense.