Dealing with a closed adoption... that is still open to my family

Oh my goodness I don't even know how to start this without writing an entire novel, but I will try. My adoption was open when it started. I told the adoptive parents that I would try to do visits at first and see how it feels, but I definitely wanted pictures and updates. I brought my family with me on the visits. Mom, Dad, Sister, Niece, and Nephew. I made it clear to the parents that I wanted to be the main point of contact, not my family, because my dad is pretty controlling and takes over everything (I was 26 when I placed my birth son so it wasn't like I was underage, but he still finds a way to control the situation). Fast forward a few months, the adoptive parents had started treating me horribly. They claimed I "reported" them to the adoption agency and they were under investigation which is a down right lie. What happened was after my son was placed, my counselor who was with me through pregnancy left the agency. They assigned me a new one and I told her all the little problems that come up with adoption and communicating with the birth parents etc in a private counseling session... and then the next second the parents are saying I reported them to the agency and they were under investigation. I asked my adoption counselor if somehow we got our wires crossed and she thought I was making a complaint or something and she said she didn't say anything and there was no investigation. I called headquarters because I thought maybe the counselor was lying and they said there was no investigation at all. I personally don't believe they ever were under investigation and even so.... nothing I said would've led to an investigation. It was little things like... they're always two weeks late on updates, their updates are only one sentense long, they won't respond to my texts... etc... nothing so serious it would lead to an investigation. I think they just wanted an "out". After that, the relationship was not going well to say the very least so I relayed that I would like to just do pictures and updates and not do visits. WELL THEN my dad set up a visit with just them and all my family without me because he knew this was happening. I was angry at my dad, I'm STILL angry at my dad. I tried to tell him that I need to heal and make this a semi-open situation. My dad was just like "Just take time off work and come".... Like, sure, come deal with these crazy toxic people that hate you for absolutely no reason... I think not. This turned into a WAY bigger thing than it should have been, like I'm your daughter, I'm asking you to please let me mold this relationship without you, but instead, he sided with the birth parents and said I was being unreasonable and that I "cut off my birth-son" etc... I called the parents and was like, Hey, I'd prefer that we don't do visits with my family anymore. I think pictures and updates will be best for all of us. They told me, "YOU HAVE NO CONTROL OF WHAT FAMILY HE SEES, YOU'RE NOT HIS MOM" which is literally the worst thing you could ever say to a birth-mom, right? I replay that conversation over and over in my head even to this day. SO because they were causing so much drama, I completely closed the adoption. I figured this is about my birth son and he is happy, healthy, and well taken care of (despite the insanity of these people) and adoption itself was a completely devastating, heart wrenching, horrific experience for me and I just couldn't put myself through a toxic relationship with them on top of dealing with the grief and depression I was already feeling. Well it is 7 years later and my parents are STILL visiting him. They usually try to hide the fact that they go, but I always find out. I know I've been focusing on the drama side of the relationship, but I love my birth son. I regret every second of my life that I don't see him and wish I would've never gave him to those people. I hate that he doesn't know me and that I don't know anything about him. I worry that I'm portrayed as some sort of evil villain that doesn't want to see him. I worry that these visits without me are going to make him hate and resent me like is he thinking..." why did everyone else come to see me, and you didn't?" or maybe he's even thinking it is because of him that I don't visit and it breaks my heart. I can't do a thing about it. I can't demand my parents stop seeing him now.. he's seven, he knows them... but every time they do my heart breaks in two. I just want it to be a closed adoption. I don't know if that is selfish, but god it hurts sooo bad to have that wound open again and again and again with no end in site. I just don't know what to do or how to even address it. I hold so much resentment in towards my own family and these parents. I don't know how to cope or how to let it go or what I can even do to stop the pain. I thought of counseling with my family, but I don't know what I even want out of it except to tell them everything that I'm feeling, but it won't make a difference because nothing will change. I'm wondering if anyone else has experienced this... or has any coping advice.