3% a month is not reasonable by past metrics. Utility companies like heating oil that didn't want to loan money used to charge 0.5-1.5% per month after the grace period back when normal mortgage rates were ~7% (APY) and car loans more like 11%(APY).

This is simply being in the business of gouging people who will end up needing to carry loans over and are better off having bad credit but never really have a point of change where they realize they need to declare bankruptcy or take other financial advice.