How to check an IT consultancy/staffing is good or not

USA
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How to check an IT consultancy/staffing company is good or not

  1. How to check the it will pay on time?
  2. How to check it will file H1B extension, I140 filling on time?
  3. How to check whether a company received any complaint or review from it is existing employee?
  4. How to check whether it blacklisted by US authority or not?
  5. Are there any website apart from Glassdoor to know about a company?