debit

I need someone who can help me with legal action on what is continuing to transpire.I had a problem with virgin active debting my account with dubious amounts and we sorted it out,as that was not enough last month they did debit me twice without my concern and any agreement and they reversed the transaction ,never come back to say we are sorry all the translation cost in all these errors, i have to pay for them .They where still not done with me they send me an email last week and entail that i owed them over R800 which i have no idea where it is coming from ,tried calling their customer line their is no answer.This is my second complaint please any one help me with legal action to this kind of