Unacceptable billing

Sometime ago I had a virgin active account where I paid a monthly fee but then this year some time I saw that they werent then billing me any longer now after 6 months no call email no.form of communication this lady calls from mbd attorneys demanding I pay R1095 in two days or 7 days latest an amount I was never aware saying my acc is in arrears threating me with lawyers etc its ridiculous and insane that I have toa pay this amount and.demading it like that .