Well, I think I might not be able to win this one

I just found out this from the "State of Wisconsin Department of Financial Institutions"
How do I Dispute a Debit?
Disputing a Debit
If a collection agency contacts you regarding a debt (or a portion of a debt) that you don’t believe you owe, there are specific things you must do to document the dispute.
First, write the collection agency within 30 days of receiving the first notice, informing them that you dispute the debt and why. Make sure your letter is dated, properly addressed and shows the account number shown on the notice. It is also vital that you keep a copy of all correspondence for your records.
Upon receiving your letter, the collection agency must halt collection activity until a copy of a debt verification is sent to you. A verification may include a signed agreement, a copy of a judgment against you regarding the debt or an itemized statement of services rendered under your name
(or the name of a dependent or spouse). It can also be as simple as a copy of the last bill the creditor sent you.
The collection agency cannot report the disputed debt to a credit bureau without also reporting that it is being disputed. However, if the collection agency reports the debt to a credit bureau before you dispute it, they are not obligated to update the credit bureau report.
If the debt cannot be verified by the creditor, the collection agency must cease collection activity on the account. If the collection agency continues to contact you regarding the debt, you should notify our office.
If verification is obtained from the creditor, the collection agency must mail a copy of the verification to you. It may then continue its efforts to collect the debt.
So, does this mean I'm liable for my spouses' debt? In this case this fee?
I'm about to write to a local attorney and see what they say.
-d