OASIS FINANCE SERVICES Recurring Credit Card charges scam not known Missouri

I received a $114.78 change on my credit card from Oasis Finance Services in July 2015.  I called my bank to dispute the charge and called the Oais phone number on my statement.  The number rang busy every time I called.   I received a second charge from Oasis for the same amount in August 2015, so it appears that they set up a recurring charge to my credit card.  When I tried to call them in August, I discovered the number was no longer in service.  I  called my bank to dispute the charge again.  My bank said they also received a busy signal when trying to contact Oasis in July.   I don't know how they got my credit card number or set up this recurring charge without my knowlege.  I believe this is a scam.