Definition of by return of post in English:

by return (of post)

British In the next available mail delivery to the sender: we will send you a refund by return of post
More example sentences
  • They also process claims by return of post (and will now pay directly into your bank account, although I still prefer a cheque as it's easier to keep track of).
  • Edwin Morgan sent his form back by return of post.
  • None of the tickets had arrived by this morning, admittedly in line with the published policy of all venues, but the RFH and Barbican tend, in my experience, to send them out by return of post.
See parent entry: return