Were you paying the credit card company or the law office? If you were paying the money to the law office and they accepted and processed those payments, you may have a case about them accepting the terms.
No, the creditor cannot ask for whatever terms they want. They must adhere to the original terms under which the debt was taken. However, if your debt is such that the minimum payment due is the $270, they could ask for that.
While judges may be sympathetic, they are have to adhere to the law.