Sick and tired of Cell c account dept

I would like to complain about cell c account department. I have been paying my accounts on there app for over a year. August payment they did not seem to find. I have sent proof of payment 7 times to different email addresses and still they keep on telling me my account has not been paid for August. Some will tell me that the payment does show. And then will put my line back on. Then another one will phone me and tell me that my account is not paid then they switch my phone off. I am so sick of this. I have 3 accounts with them that has the same problem.