It doesn't sound like this would have helped in this particular case since they were unable to contact the customer.
That's hiding behind the T&Cs instead of owning their decision not to even try because there is nothing in it for them.
Do you really never get e-mails from various companies every few weeks telling you that the terms of service have been updated?
I think I get one from eBay alone every other day.
The T&Cs are an agreement between the parties. That agreement can be changed at any time if both parties agree. So they just need to ask.