Venting

Hi evry1!! hope u are all doing well :3

It might be a lot of words and may be too much info but I just need some advice. A little background info. So last year , I was lending my older sister (32) money for herself and her girls. She would message me that she needed money for a wedding gift, clothes, food, gas, personal items etc. I felt bad because she needed help but also I wanted to make sure my nieces were able to eat and have what they needed. So around October of last year, she messages me asking how I would feel about having a pen pal? I honestly figured it was for my oldest niece because she mentioned about writing letters. So I say yes and she texts me right after that it's for her boyfriends brother whose in prison. She even wanted me to start doing phone calls as well. I honestly wasn't comfortable with it but figured she's my sister, maybe the guy is in their for something like fraud or nothing violent. So I agreed. After talking for a bit with my sister to get more information I asked what he was in their for? She said she wasn't sure but she gave me his name. I search him up and turns out he tried to murder his 14 year old girlfriend and was serving a life sentence. I told her this information and she said how it doesn't say how the girl antagonized him to do it , basically excusing him for it. That really upset me. My sister never read the court documents, the guy locked her in his car took her to a neighborhood and started stxbbing her almost killing her and left her physically disabled for the rest of her life. The girl was a victim , she shouldn't be blaming her at all. 

After finding this out I sent her all the information of the case and she still wanted me to write to him because he was "lonely'. I didn't want to write to him. So I made excuses about how I had finals and wasn't able to. Around this time my mom kicked me out, I had a lot of stress already and my sister in total owed me over $460. I really could use this money at this time. So I ended up messaging her, apologizing about how I felt uncomfortable writing to this guy and if she can start making payments to pay back what she owes me. I was honest with how I felt and told her I am sorry. She did not like that at all and got so upset with me. I never felt so low. I lost everything that day. My sister , my nieces , my mom, my family. No one was speaking to me. I didn't do nothing wrong for asking for my money. She sent me horrible messages calling me a bitxh, loser, retarded, and how im just like my mother. She sent so many texts. She spread lies throughout my family of what I said even though the texts say different. I never once attacked her. Not once. I never went against her family or her values. She cut off contact with me 9 months ago. I haven't heard from her or seen her since. 

Now 2 days ago.

I get off of work and seen a bunch of text messages. It's my oldest sister, my 2 other sisters and my younger brother. we are all in a GC and she is telling us that she is getting married and she wants us to be at her wedding. I never responded and she sent a text to me to read what she sent because there is a wedding I'm wanted at. Im hurt. I really am. And im stuck. I don't know what to do or what to say. I started living life like I never had nieces or an older sister because what she said to me really hurt. And now she wants me at her wedding like if nothing happen, like she didn't cut off all contact with me and call me such horrible names and slurs. I don't know what to do or say. I want to call her and tell her how I feel but what if I go through the same thing again. I don't want 2 get hurt again.

I know it's a lot but do you guys have a recommendation or advice for what I should do?