Complain about the workers who fail to do their job properly

I'm disappointed with Cell I have contract phone last year 30 December and 2020 I visit one of the stores in Clermont cape Town I went there to update my new account one of the guys who work there assist me take my new account he said he will put on system so that debt order can debt month end January 2021 i was waiting for debt order to take the money no notification even now February still the same I'm disappointed because my account its been canceled due to one of the worker who failed to do their job now how to fix this because now I can't connect end when I Adress the issue to service providers the refer me to debt collectors how to be sure that is the legit company to pay them please help me with this issue.