Nimble Group - useless company

I am trying to get information from Nimble Group (which bought Cell C debt) with absolute no success. I have a pending query on my final account with Cell C and the debt collection companies keep on changing. Each time I have to start over explaining my query (and give my evidence) and insist on the evidence from Cell C. Nimble Group is a pathetic company, and nobody response to my numerous emails. Their harrasing call center agents are pathetic !! No one apparently knows I have a pending query, and keep calling, but NO ONE answers my emails send to ***. Pathetic useless company ! I am trying to resolve this matter but with a non compliant company like Nimble Group this is simply impossible !!!