Keep calling and saying I have an outstanding balance

I have been receiving call after call after call for about 3 years now telling me one is from a credit card I had with HSBC with a balance of 300.00 in 2006 so I paid that card off (a total of almost 700 dollars) in aug of 2013 bc I knew I owed it. Now I am getting threatening calls from Orchard Bank and don't remember ever having an Orchard Bank card and have never received anything from any bank called Orchard Bank saying I owe a past credit and never say how much I owe. They just say I owe money and are telling me they are taking me to court. They never give me anymore information than that. I get calls several times a day and they won't stop calling me or give me any other information. I dont know what to do to make them stop either but its getting old! Its not on my credit report and I have never received a letter from anyone about this matter.