|Let me guess, the person who changed these no longer works there?|
Your first step would be explain to this person that what they did was criminal and you will file a complaint and have them arrested if they do not provide the password.
This person is also liable for all your downtime, tech specialist time, loss of business, etc. You can have your insurance company go after them after they have been arrested.
We can't help you with passwords due to the rules of this forum. Most forums have the same policies. You would need to hire someone local who knows how with physical access to the server gain admin access.