The Ramona Post Office, postal investigators and the Sheriff's Department are working together to figure out who vandalized the mailboxes.
Residents say this is not the first time it's happened, and the U.S. Postal Service confirmed.
"It started in November of last year and it kind of died down after we had some arrests here in June. Now you have another round of it," said Laura Lewis, Ramona's postmaster.
For the time being, residents are asked to pick up their mail at the Ramona Post Office during regular business hours.
Some of the neighborhood boxes have been repaired. The post office hopes to have all of them fixed by Monday.