I can hear people clearly on the phone, but they can hardly hear me even when I have the volume way up. Is this a battery issue? Mine is an old portable, but I love the clarity of sound that it produces. Also mine says to use only #3301 battery. I have been using a 86416 battery for years. Model #CANADA 3999 101 611A. Please advise, Thank you, firstname.lastname@example.org.