I find the "negotiate with collectors, they'll take anything" advice all over the internet, but in reality I've never been able to negotiate with collection age

I find the "negotiate with collectors, they'll take anything" advice all over the internet, but in reality I've never been able to negotiate with collection agencies. They will do payment plans of a couple of months, but they will never accept less than the full principal, which is ridiculous. I always offer, they say no, call ends. Or I pay the full balance. Dealing with commercial lenders and banks is different. But consumer debt is another animal.