Postboxes which were smashed open just before Christmas are expected to be repaired by the end of January.
Boxes in Cove, Kilcreggan, Clynder and Helensburgh were among 14 attacked on the night of Sunday December 22, with vandals being blamed by the Royal Mail.
A Royal Mail spokesman did not confirm whether any items had been reported missing, but said there had been a collection earlier that day.
He said the boxes were being repaired and, where necessary, replaced.
“We plan to have all of the postboxes back in service by the end of January and apologise to customers for the inconvenience caused by these mindless acts of vandalism,” he said today (Monday).
“In the meantime, customers should take mail into post offices or post in nearby alternative post boxes.
“If any customer has any concerns about their mail, they should call our customer services team on 08457 740740.”