E-mail Deliverability specialist to Office365

Job ID: 32367234

Budget: €250 – €750 EUR

At the Zotonic open source project and at LearningStone.com we have been experiencing problems sending mail to Office365. Mail to outlook/hotmail is ok. We have knowledge of spf, dkim, dmarc etc and have been searching for the solution for a long time. We find that there is some problem in reputation: in some cases mail gets sent if there is no HTML in the mail.
We are looking for a technical specialist that can help us with this problem. Do you know what effects the deliverability and/or do you know your way to Microsoft to get help?
We are NOT looking for an exchange specialist for configuration but advice on our sending deliverability.