stop call log and voicemail sharing between devices

QDEskimo wrote:

yes I prefer to keep the information segregated one for work one for personal use

Then you'll need two Apple IDs. You can use Family Sharing to share content between the two devices.

There's some really good information here:

How to “unshare” an Apple ID - Apple Community

Do you personally own and exclusively use both iPhones? If not, immediately stop sharing the Apple ID.

Make sure that each family member has a unique Apple ID - Apple Support

QDEskimo wrote:

yes I prefer to keep the information segregated one for work one for personal use

That is perfectly understandable and a practice I have also used. But along with that, I strongly suggest you use separate Apple IDs for each device.

Bear in mind your employer has access to everything on your work iPhone - your personal material included.

QDEskimo wrote:

Now my call log and voicemail is being shared across devices and there’s no way to stop it from happening.

That's correct. There is no way to stop if from happening as long as your sharing an Apple ID across the devices.