Nimble collections and Zone fitness is a ****

I have been told that Nimble Debt collectors have been call my mom and my aunt looking for me.

I called them today to find out why are they looking for me exactly. I was told by one of agents that I have a account with zone fitness and I am owing them R6000. I never open the account with any gym club or zine fitness. Can you please sort this thing out with zone fitness and stop calling me. I want my name to be cleared because I never joined zone fitness in my entire life.