Bad service

My account was handed over to SSDA early this year , I’ve been paying them consistently on a monthly basis . However Cell C consultants call me on a daily basis asking me to make payment to them . So who exactly should I make payment to ? Cell C or SSDA ? I spoke to Monique , a Gavin called again and placed me on hold for over 20mins for no particular reason , all I heard was people laughing in the background and no one to jump on the phone and assist ? I spoke to Nthabiseng Lebese and she kept sending me from pillar to post .