TERRIBLE CUSTOMER SERVICE POST SALES LEAVES CLIENT WITH DIS SATISFACTIONS

I send emails to cell c requesting them to assist with relocating my fiber connectivity from my old office to new premises last year November 2019 and no they didn't help me, and i relocated my business, and on 19 Feb 2020 they suspended my account, and ever since then continued to try ask them to help me with connectivity until i saw that they were not going to help me,i send them dissatisfaction letter email and still they ignored me but then send some debt collectors to collect premiums i refused to pay due to no service rendered in all that time.How could they expect me to pay for the service that i didn't receive,they have really inconvenience us as a small business and made us lose clients as we conduct most of our business online.