letter of demand - black listing

i apparently went into a 12 month contract with this **** bag of a company, they deducted R399.00 from my account, one month later another R100.00, there after i made a stop order on my account, now 3 months later im being threatened by court summons and to be black listed for an amount of R633.00 ( the amount to pay the remainder of the contract ) no paper work was signed, no phone calls were made, STAY AWAY - THIS COMPANY TAKES ADVANTAGE OF PEOPLE WHO ARE IN DESPERATE SITUATIONS