According to the FCRA, you absolutely have the right to request validation of a debt at ANY time that it is on your credit report (as long as the request isn't "frivoulus"). What's more, you can request the actual name and contact information of the person who confirmed the debt info, AND you can request a copy of the documentation related to the debt. Further, if the collection agency or debtor can't provide it within a reasonable time (usually deemed to be 30 days), then the credit reporting agency MUST delete it. However... that doesn't mean that the creditor can't report it again!
Although, it probably won't help with a collection agency - they usually have the original debt documentation, or can get it rather quickly, especially in this instance where the debt is fairly recent.
You can try contacting the original debtor (the doctor or hospital) and tell them that you will ONLY deal with them, and that you want a deletion letter agreement before you will pay. However, the sad truth is that you are most likely going to be stuck with this collection on your record unless you can somehow prove fraud or negligence. Doesn't sound like you can in this instance.
One final warning... don't pay ANYTHING on this unless you decide that you are just going to pay it off, or until you get a deletion letter. The moment you pay anything on it (even a penny), it resets the 7 year clock!
Good luck!