I've been a paying Heroku customer for a decade, with multiple businesses (a surf company, tennis reservation system) and personal projects hosted without issue.
On Tuesday, I woke up to sites down and my login not working. No emails from Heroku. After emailing support, I got an automated response that I'd been banned for violations of the Acceptable Use Policy. No details, just instantly dropped.
I've sent 10s of emails to every Heroku and Salesforce support and security department, called the SF offices, and tried social media. I still have no idea why my account was suspended, and apparently I have no recourse to get my company data back (backups, credentials...everything is through the Heroku login).
Heroku is trying to put me out of business, I recommend you leave them before they do the same to you!
Story time: I worked for a major marketing firm that did this with Facebook. we would see accounts go down every once in awhile and it turned out the managers of the companies that cried foul were doing foul things which we would have to resolve (bonus: extra $$$ Too). One Saturday our monitoring started chirping only to find all Facebook accounts were deactivated. It took us 10minutes to realize we did not change our tooling to support their api changes. These are well known name brands that were completely down. That was the first time I have seen an entire company scramble to resolve an issue, but we were back up and hobbling around within 2 hours.
Always separate accounts.