Incorrect billing and no proper explanation given

Haven't used dtsv in months, in January on the 25th I checked the amount due using their WhatsApp line and it was R112. Last night when I checked again to reconnect services it had gone up to R1227. Went onto their LiveChat and was told it was due to termination, asked them who terminated what and when, Consultant just couldn't explain and kept on saying I need to pay the amount. All I want them to do now is cancel the whole thing cause clearly they cannot bill properly.