poor service

hi I have a contract with cell c, so this is my 2nd pone iPhone SE. 1stly their prices increased twise already ,isnt a contract fixed? last year I changed my salary date and asked them to changed it to the 21 as I get paid 20 due to the fact that they don't have naedo and they debt my account before I get paid which is more bank charges for me , i found out they dint change my due date they. so my account went to arrears, January this year I called them to confirm if my date have been changed and to make payment arrangement, the lady I spoke with ensured me that they changed it and I made arrangement to pay extra but not full amount as I can not afford R960. few days after that I got an sms stating that my account is handed over to NuDebt I must call them for arrangement. on the 20 February a debt order went thru and the reference is "Nubedt Cell. I called cell c Thursday regarding this ,they know nothing about nudebt and I told the agent that they sent me an sms stating a handover, I called them since last week Thursday, Friday en Sunday still my query hasn't been sorted. this morning I sent them an email. I never experience any thing like this . if I had money I would settle them and I would never recommend them to anyone for that matter