Can collection agency charge you their fee for collection?

No they can't it's against the law. However the original creditor is allowed to add collection fees as long as the underlying contract allows for it. For example medical intake forms often allow for...

Yes. It depends on your state. Most states allow up to 30% of the balance. However this depends on the type of debt incurred by the debtor.

Typically it is NOT the collection agency that adds "extra fees". When the original creditor has exhausted all of it's internal collection efforts, it sends the debt to a collection agency. The...

this depends on a few different things. one, is the collector "assigned" to collect the debt by the original creditor? if so and you agreed in the original contract to do so, then you are stuck with...

Yes, any and all expenses that the lender incurs can be passed to the customer when they are attempting to collect a debt.