Certification Academy review: Non payment of invoice after work was successfully completed!

I have been trying to collect on an overdue invoice for almost a year now. They have paid $500 on a $4000 invoice so they know it's legitimate. All I'm asking for is to be paid. Not sure why they have this complaint board when none of my concerns have been addressed. It would be awesome if someone would pay me please! I am having a hard time understanding why this company cannot or will not pay me after asking for almost a year. Do the right, honorable and professional thing and just pay the invoice.