The people you deliver to every day are real people, leading real lives.
When someone has paid extra for next day delivery, they normally have a good reason. Perhaps it is an urgent item, or maybe they just know they can wait in all day that day.
When it doesn’t arrive, they get a bit annoyed.
When they check the online tracking and see ’19:28 delivery attempted, card left’ they get even more annoyed. Particularly if they know it is a blatant lie because at 19:28 they were within 5 metres of their front door, and there is no card on their doormat.
When annoyed people make complaints by email, a simple acknowledgement is better than silence.
Having a message on your website telling people they can simply call the number on the back of their failed delivery card, assumes that none of the delivery drivers are either a) liars who didn’t leave a card or b) incompetent and put it through the wrong door, which is clearly not always the case.
When it still doesn’t arrive the following day, that annoyance transmutes into a desire to tell the world about the bad service level, and a determination not to buy anything from companies which use Yodel.
Are you scared of publishing your phone number? Worried you might be inundated with complaints? (I’d be particularly keen to know the number of the Gloucester Depot)