Cox remote falsely claims batteries are low.

I have been buying new batteries Duracell (the type should not matter) Test them and they are great then put them in the remote and within a week I get the critically low message on my screen . The remote  is draining the batteries excessively  because I retested them and saw it. There is a problem  Houston...    I'm bringing it in for a new remote... do I need a new box as well so they match... ?