Cell C: HORRIBLE SERVICE

I've been trying to get hold of Cell C legal department since April 2019....Nu debt has been smsing me, stating that I should pay my outstanding balance. My payment was made in April already and everytime I tried calling the legal department I was told they're on strike. Customer care is unable to assist with a paid up letter, they sent me to cell c store nearest to me to get a paid up letter but the consultant at the Cell C store gave me a number (customer care call centre) to call cause she's not authorized to give me a paid up letter. I've WhatsApped Nudebt on the whatapp number they've provided me with, I sent my personal details and proof of payment so this matter could be resolve, but my nothing has been done. My credit score is affected because of this,and hello Peter is my last resort.