Switch Collection Agency

I was wondering if someone could give me some advise. I owed Seaman's about $2500. Now the reason I came into contact with CR is because I decided to do a credit check on myself and saw that my once excellent score of 757, all of the sudden became a 622. I realized I had a Seamans bill that I totally forgot about because when I made the purchase, they had a special in which you pay your first bill in a year. Hence my first bill should have been payed Feb 2006. The last bill I ever recieved from Seaman's (HSBC) was perhaps September 2005 (I know cause I looked in my files), so the bill was completely forgotten about UNTIL I did a credit check. When I call Seamans they told me they no longer can help me because they sold my debt to Corporate Recievables. I then called Corporate Recievables and wanted to straighten this out HOWEVER!!! when I spoke to their "supervisor" it became an all out verbal war because I could not pay them the full amount. He became very abusive and knowing my temper I lashed out just as equally. Now I know I am completley responsible for this debt, HOWEVER I refuse to pay them one dime. BTW they called my house and verbally abused my sister, after she told them who she was and they said she was lying... that she was actually me, covering up. Regardless... does anyone know if I can switch my debt to another collection agency, because I really don't want to pay them nor deal with them.