Bad service with cell c and CSS lawyers

Good day I have paid my last Cell C amount last year, send proof of payment. And still handed me over to the one and now other lawyers and know CSS is still sms and calling me every month for the R105 that they cant allocate for a year I have send email after email to cell c and to all the companys that cell c is handed me over to. And no one can fix the problem I wil not pay it again. They cant even alocate the paiment I payed a year ago. This is horrible will never open a contract with cell c again. This is getting ridiculous.