You might want to check further into this. Many times a collection agency will buy the debt from the original holder. Thus the record will be shown as "written off" (Something to that effect), but then you are in debt to the new collection company.
You don't need to change banks. You can either close the old account, and get a new one, or as you have already done, put a stop payment to the collector. It's not the banks fault this happened.
I know this from being the collectee...not a collector. I still owe so much. eeek. And never ever do those Online one hour loan things. I did several during my last relapse...and it's like 400% interest. I kid you not.