When I first looked up this number after a missed call from them, all I could find was that it was associated with Citi. They called me again just this morning, and I answered it. Turns out it was One Main Financial. They've been harassing me before and even since I filed for bankruptcy; they've been calling me for almost a month after I officially filed, which is illegal. Finally today I actually talked to someone, and it was the singular most stressful phone call of my life. They insist they were never notified of my bankruptcy and so it's perfectly legal for them to call me. That's bull. They said "All we're doing is collecting on the money we lent you in good faith..." with 22% interest, yeah. After I gave them my attorney's name and number and told them to call him, they kept insisting that it was my job to have him call them. Then he asked if I was going to make a payment today. The call went on for several minutes, and when I finally hung up I felt like I was going to throw up. They're really good at that harassment thing, and making one feel even worse for being forced into a situation that no one ever expects or desires to go through. But I know my rights, and they are way outside the law with what they're doing. I told them over and over again to stop calling me, to which they replied that they had the right to since they "hadn't been notified" of my bankruptcy, which is simply untrue. I've heard of them harassing others in this same manor as well. Whatever you do, don't get a loan through them – they're criminal vultures with no regard for the law.
I just wanted to post this comment in case it helps anyone else who's also being plagued with calls from unknown/untraceable numbers.