Actually I don’t think it is Apple issue, because this never happened before I switched. That link does not solve the issue I’m facing, thanks for trying.
for your information on my iPhone under Settings/Messages/Send & Receive/iMessage
it shows "Use your Apple ID for iMessage", iMessage has a separte login for Apple ID which you don't need to do it in order to use iMessage on phone with your mobile number.
I copied the below information from apple support website, I believe what you want can be acheive by Sign Out under Send & Receive or change your Apple ID password which would force all your device to require re login which could be a hassle for nevertheless workable solution as stated.
I am no expert but I have be using iMessage with just number only. hope this can help you.
Remove your phone number
If you don't want calls or messages for your iPhone on your iPad, iPod touch, or Mac, you can remove your phone number. There are two ways to do this: