I would open a dialog with the owner of the IT services company. If the owner does not take your concerns seriously or the staff doesn’t step up their service after your conversation, then its time to begin your transition.
It sounds like there’s a trust issue, so quietly gather your documentation and ensure you have administrative access to all of your systems. If you don’t have a handle on what systems your company has, or how to access them, you might want to consider bringing in a professional to perform a network audit, develop a plan and execute a graceful migration. If you do bring someone in, make sure they understand the delicacy of the situation.
Regardless of if you transition to another provider, you should have full documentation of all of your systems. If your service provider is withholding information or does not share all of their client data with you, it’s time to have a frank conversation with them about transparency.
Hope this helps. We handle transitions all the time, just shoot me a message if you have any specific questions or concerns.