All posts like yours always get the spam replies.
Let's dive into the OST file in depth by reading https://support.office.com/en-us/article/Introduction-to-Outlook-Data-Files-pst-and-ost--6d4197ec-1304-4b81-a17d-66d4eef30b78?ui=en-US&rs=en-US&ad=US
Aha, there is usually not much in an OST file as it's only a cache of what's up on the Exchange Server. As such you need to get back to your Exchange Server administrator to get the rest of what you are looking for.
By definition, the OST does not have what you are looking for.
However there are plenty of bad folk ready to sell you OST to PST convertors and data recovery. If they offer such, it's been a spammer to date.
Here's the deal, there is a file .ost, but neither Exchange, nor of the mailbox to which it was attached. Now in this file I need to get all the data ranging from emails with all attachments, to the calendar and deleted items folder. If the file attached to the new mailbox with a similar name, MS Outlook 2003 starts to swear that this file was created for another mailbox and accordingly nothing opens. Here in brief and all. Can anyone advise what to do?