2 years ago, I worked on a private company, sudden occurrences happened and it left me with no choice but to apply for a loan with a total amount of $2,000. We both agreed that they'll gonna deduct it partially on my salary until I fully settle that amount. Just recently I keep receiving phone calls from unknown number but they leave no messages. After researching a number, I found out that it is a debt collection agency which is https://www.backdoorhires.com/ Since I am pretty sure I don't have any outstanding debt, I return a phone call to them. They asked me to pay the remaining amount I owed from my previous company. I was under the impression that I fully paid that amount before I leave the company but now I was frustrated when they said I still owe $900 more with the interest. They said if I will fail to settle this amount they will sue me regarding my unpaid debt. I am so worried right now. Can anyone here tell me the best thing to do. I would highly appreciate your comments and advice.