Being sued for a debt not on my credit report?
I hope this is the right place for this question. But I'm currently being sued for a decent amount (2k) for a debt I don't recognize and is not on my credit reports? A little background, my ex got me into a decent amount of debt (not a huge amount) over 7 years ago Because of that my credit score plummeted so I haven't opened any credit cards or got any loans in those 7 years simply because I always got denied, which leads me to be even more confused about this debt.
I got a summons to go over my income/assets, but before that, my question is: is there any way to find out what this debt even is? Who it's from, when it was created, etc? The plaintiff is a debt collector and it doesn't say who they got my debt from.
Any help/advice is appreciated!