Hello seems like you need a third party trusted program which can Recover your deleted emails.
If you want to give a try to this OST Recovery Software
it can recover your email files and folders and everything your .ost file carries.
After recovery you will be able to convert your emails into different email formats, PST, PDF, Office 365, exchange server etc.
Download from this link OST to PST Converter Software
OST and PST both carries emails and folders a complete database of your email profile. So you need an Outlook email Recovery software.
For sure you will be able solve problem and recover all emails.
I am suggesting you as I have used already this program and suggested because they are great in providing assistance on real time.
With This Advance OST to PST Converter Software
you will be able to recover entire OST files and folders and able to Convert OST file to Outlook PST format.
You can Convert Multiple OST file to Single PST format
Faster Conversion OST to PST email format like 20GB, 30GB, 50GB huge email database easily and smoothly with this best OST to PST Converter