Vonage keeps on charging account after several cancellation

Last Nov 01, 2010 I contacted vonage regarding my mobile service.  I was told my phone number could be transferred to vonage, so I gave my credit card information and set up an account.  The same day, I was told my number could not be transferred to a vonage account so I asked them not to open an account for me.  I was told it would take a few days, but the account would be closed.  Jan 01, 2011 I saw they were still charging my account, so I again cancelled the account and asked for a refund of the charges to my account.  They said they would cancel the account but could not refund the charges which is ridiculous.  Feb 19, 2011 I contacted them again because my account was charged on Feb 01, 2011.  I again cancelled this account and asked for a refund, they cancelled my account but refused to issue a refund and I'm getting pissed off.  I cancelled the credit card they were using to charge my account to ensure they could not charge my account again.  On March 01, 2011, they managed to charge my account AGAIN.  Today I contacted my bank to report these fraud charges and vonage to find out why they charged my account.  I was informed my account was still active, so again, I went through the cancellation process with vonage, their customer service really SUCKS!  Lets see how many times it takes to cancel this fraudulent activity going on to my account.