manipulative grandparents???

first, my grandparents take care of me, as my mom walked out of my life when I was 3 and my dad when I was 13.

second, recently (as in a few hours ago) we got into a very large fight. I was at my boyfriends house for a couple of hours today, as I normally am, and they’ve know about this for a while. they’ve met him on many occasions and they have expressed to me and him that they trust him and that they like him a lot. so tonight my boyfriend asked if I could sleep over, as it was late and we were too tired to take the 45 minute bus ride home. he asked over the phone and they responded very nicely to him but when I came on the phone they started screaming. I tried to call them down very nicely and they just got louder. then when I asked if they could pick me up, because it’s quicker, they responded with the fact that they’re drinking. they called me around 3 more times and they yelled at me the whole time so naturally I got scared and just ended the call. my boyfriends mom offered to drop me home but then my parents called me and said they were coming to get me in two hours. so for the next two hours my boyfriend and I just laid in his room. when they got to his house he took me outside and waited at his door to see me get into the car. thy immediately start screaming at me telling me that he’s a horrible boyfriend and that he doesn’t even care to bring me home and that’s he’s a liar and that his mom is a liar and that i’m a liar. finally my grandfather breaks into a roar saying that when he first met my boyfriend, he said that he was only on the relationship for the sex and that he’s gonna break up with me when I go to college. I called my boyfriend in a hysterical fit of crying after my parents said they would call the police to take me away. also they told me that I was not allowed to leave the house until I was 21 years old and called me a whore numerous times. when I called my boyfriend, he told me that none of that was true and that that’s a lie. I believe him because he’s shown me nothing but love. i’m wondering if it sounds like my grandparents are abusive and/or manipulative.

1. if that was the truth and that’s what he said, then why would they allow me to be with him in the first place?

2. if my boyfriend didn’t say that, why would they lie to me about that?