Deskphone Rings, does not allow me to answer the call

I already walked thru a help chat 2 weeks ago on this issue and it is still happening.  My desk phone rings, i pick it up to answer and it keeps ringing, will never allow me to take the call, then goes to the computer app,  then the app on my cell phone.  I want to only use my desk phone when I’m in office and use the computer app or my cell when I am working remote.  This should be as simple as the press of a button to use my desk phone when I am in office and it’s not.  Any tips for this constantly annoying issue?