MBD collection on *****ulent debt

I was contacted by MBD early this year with regards to an account *****ulently acquired with Vodacom in my name which Vodacom that was handed over to MBD. I advised MBD that I did not open this account and opened a ***** dispute case with Vodacom and made MBD aware of this to date I am receiving daily harassing calls from MBD try to make collection for debt that I did not take out. MBD and Vodacom are sending me from pillar to post and this debt is currently listed as in default on my credit record , please help