Can I be harassed like this illegally?

I would really appreciate if someone could give me some advice or positive feedback on my situation. I have a relative who I have not seen in approximately 3 years. We reside in different states and are only cousins. We do speak on occasions but are not close. The relative financed a vehicle through Chase and has missed some payments. I was never listed as a reference or relative in the agreement. My relative has never known any of my addresses Ive had and I only been in contact with the relative through other relatives that reside in their state. Ive not lived in that state since 1995 and my last visit to the state was around 2005 year. My husband and I bought our first home in 2007. Prior to that we were both military and stayed in military housing. I started getting phone calls in Dec 08 from Chase Auto Finance about the relativ’s vehicle. I explained to them that I dont know the relative address other than the city and state. I do not have any contact information for the relative other than a cell phone giving to me by another relative of ours. I even gave them the cell number and asked them not to call me again. I thought it was over but I was so wrong. Over the next 3 months Ive continued getting calls atleast 3 times a day every single day up until yesterday. I must also state that during all of this Ive sent 3 certified letters to the address that the collections agent gave me stating not to contact me please. I will not ignore any calls from them because its my phone and I have nothing to hide. Yesterday a repo man was sitting in my driveway blocking my garage. I asked him what he wanted and he at first was very rude. He said I had to give him the car. I said what car. He asked if I was the relative. I said no. I had neighbors outside as well because we going to bbq. I opened my garage for him because he said I had to legally, so I did and no car was in there. Ive never financed a vehicle before and dont know the law. He was very shocked that the vehicle wasnt actually there. Then he sad he was so sorry that I had being going through this and told me that he would personally call Chase about this matter. I asked the repo guy how they were getting my information and he stated that it looked like they were probably searching all of my cousin’s relatives to find the vehicle. I received another phone call this morning at 8am from the same collections agent and once again asked her how did she get my information. She stated that a call was place from my home regarding the vehicle and they traced it. I said traced? and she said yes. I said that couldnt be true because I have my phone records and only 2 calls have been called to the Chase number and both calls were me calling back trying to explain this. She then stated it wasnt her problem and that they are going to keep calling me and coming to my house until the vehicle is found. Ive contacted the relative also through another relative and found out they had did this to 3 other family members in that state as well. Those relatives and me all shared the same last name at one point of time. How can I stop this? I dont have money in my budget for a lawyer at this time. Please help me someone because my husband and I are going crazy over this. Ive recorded all the calls since January and my husband and I have security cameras (for my child’s safety) in the front of my home that recorded the entire incident.
Sorry ,I meant can I be harassed like this legally.
I reside in TX and the relative reside in TN
This is my first time posting and Im sorry if I didnt post it right. Thank you all for any answers that you have contributed and I may just have to get an attorney. I was told by someone that this board would be very helpful.

prevent home repossession