Cell C - lack of response / impatient CSD

Please can the collections department respond to my emails about my full payment made? I am not getting email response, and I paid up my full payment on my account on 15/7/2021. CSD department, cannot help. I had an impatient lady called Thandeka Mhlar? (she didn't seem to want to spell her surname properly), getting very irritated with me, asking me a security question, for an account that I can't remember, last used more than a year ago. Not impressed by her patience at all. Thank you