Car Accident Issue, They aren't leaving me alone Options

[MaskedMan]

Alright, so lately i've been stressing out a lot, and i really need help here. I was involved in a car accident about few weeks ago when i car hit me from behind pushing me into the car ahead of me. I damaged the car ahead of me a lot and the car behind me drove away and we didn't see who it was. We didn't file a report, and we agreed to handle this outside of insurance. I ended up paying $2,000 and had her sign a paper saying that i had paid her and all payments and concerns are complete. But now she is calling me, telling me that her insurance company wants to charge me for all kinds of stuff like medical and therapy and stuff. I guess she decided to go ahead and call her insurance company either way without telling me on the day of the accident. Can her or her insurance company do anything to me after i paid and she signed the paper?

[MaskedMan]

Well actually now that i think about it, i shouldn't have paid her anything, but i did, and i guess i just wanted it all to be over asap. But it seems like even a month later, it's still coming after me. All i really want is this all to end, and i was actually going to give her the $3,000 to shut her up, but is it really going to end after the $3,000 anyways? I just want to get back to my life becuase i can't even enjoy life or anything with this huge problem always on my mind. I just want to go back to my simple life of going to work, and then coming home to work on my car. Thanks for all the input guys, i really appreciate it as i really have nowhere else to turn. I work all the time so i don't really have many out of work friends, and my family lives thousands of miles away so I don't have anyone to ask for help with this stuff. Thanks, I just don't want any of this to get worse and i want it all to just go away already.