It pains me to see even occasional defenders of Heroku. They're not the company they were 10 years ago. They've been gutted and left for dead years ago but the product was so good nobody noticed until now.
They're not to be trusted as your platform. They simply don't have anywhere close to the manpower required to run such a platform. This was a when not if situation.
If you're still on it, make your plans to move away now. Time is ticking until a major outage or another security incident like this one. See my comment history and related threads for more. Specifically this summary: https://news.ycombinator.com/item?id=31374048