Altech Netstar
Refusal to Cancel My Account

In May 2011 I received a call from Alvina of Netstar about my outstanding account, I asked the balance then informed her to cancel my account as I was unepmloyed and couldn't afford their services. She said I must swend her an email wich I duly did.
A month later Marius calls me about the same account, he gives me Netstar's bank details, he asks for proof of the email I sent to Alvina bcs the account is not cancelled. I forward him the email.
I pay the outstanding balance and Marius says he will close the account.
Netstar came back last year handing me over to Vvm attorneys for non payment.
I give them proof of payment, emails to Marius and Alvina.
They come back saying the account was never closed I owe them for June July and August.
Their employees did not close the account so I am liable!!!
I have never received a statement I was unaware the account is still open!
How am I liable!!