online credit card fraud?

hi to u all i was a recent victim of an online credit card fraud….they have used my debit card and now my bank account has a over drawn balance of $-500 i spoke to the described merchant of the unauthorized transactions (they have a phone no with transactions) all of the transactions were made online……when i called them to get the refund they say i did all the transactions and the have all my information including my address, my name, my IP address ……and i called my bank to dispute the charges the bank said to dispute, the charges has to be posted to the account first..
when the charges are disputed with the issuing bank, the bank is going send me an affidavit to sign and they are going to do an investigation into it

my question is because the merchant is calming that i did all the transactions will i get into trouble if i file a dispute
should i talk to fbi’s online credit card protection center should i file a report with police…what should i do…….
but my fear is will they get me for doing that because like i said the have my IP address….but i know today computer hackers can easily spoof ur IP address and pretend like you and they also have all other info like my name , my address
yes they are from the same merchant….and there are 10 to 20 separate transactions from the same merchant …….
its a online company (pay per view) that offers to download movies like porn sites…..so thers no shipping address or anything everything is done online….