Debt Collection Agencies: Is there a minimum amount?

I have an amount outstanding from one of my clients for €300. It's not huge, and I wouldn't normally be bothered chasing it, but the person is acting very unethically and I would love to see the money taken from her.

Even if the debt collection agency took €250 and only gave me €50 it's better than nothing, and it would mean she would have been forced to pay.

Does anyone know of a debt collection agency willing to take on such small one-off amounts?

I have found none willing to take on anything less than €1000 unless you had a few that totalled €1000 or more. Have you tried the likes of intrum etc?

Also their success rates are low especially when dealing with unethical persons like the one you have described.