After deep investigation, we found that abuse mainly came from API, so we decide to remove the number limit on cron job, and keep the limit on API request, but adjust the quota to:
Free: Max 100 daily API requests
Starter: Max 1000 daily API requests
Plus: Max 2000 daily API requests
Max: Max 5000 daily API requests
Hope that our users will enjoy the change, you can set up unlimited cron job again now!