To start I want to make it clear I have no experiance with office 365 or the associated exhange stuff, and I would never personally recomend such a package to my clients, hence why I am totally in the dark about this.

I have taken on the management of IT for a small buiness and have been tasked with migrating away from office 365 software to get costs down.

There were 15 computers and each had an email address and access to the microsoft 365 software suite. So far I have changed all the accounts onto an "exchange only" plan, removed office 365 from all machines, and migrated to stand alone versions of MS office. Which is great, saving them lots of money on subscriptions already.

The exchange only licences have come via a reseller purchased by the previous IT technician. It appears the company has been paying the technician and he has been purchacing them from the reseller.

There has been some disputes between the company and the technician and he has threatened to hit the kill switch on the 365 licenses and seriously throw a spanner into the works. So we want to migrate away from the reseller and regain full control of the licenses (on the down-low if at all possible.)

So basically my question is; can we descreetly remove our relationship with the reseller on the office 365 admin account from our end, while either maintaining the existing licenses, or purchase new licenses from MS directly without loosing any of the configuration or data currently held in the exchange mailboxes!

It is my understanding the reseller relationship can be deleted in partner relationships, only it doesnt give me an option to delete. Also I believe if I could delete it, it would then take all the licenses with it and we would loose the mailboxes?

Should I perhaps purchase all the new licenses and then assign them to each user before breaking the reseller relationship? and is it possible to switch these licenses without losing the mailboxes? It is my understanding that if a user is reverted to unlicensed then the mailbox gets removed?

Any advice will be greatly appricated.

I don't believe you. This was spammed before and here you are again.
theblogpros.com/2019/01/16/office-365-license-migration-advice/ has the same text and you took no pains to alter it.
It was also posted with same text on Daniweb.

You appear to be a shill or spammer. Change my mind.