Dishonest Service/Practice

I purchased a Withings Home device.  When I contacted service, I was provided a shipping label and I duly returned the device to Withing Home.  Months go by without a word.  When I inquire, I receive an email that my request is closed I have to create a new one.  The Website portal asks me for the serial # of the device I returned!!!  Really, can't the person just writing the email address the issue: where is the device I mailed in and what is the status on repair or replacement?