I'm sorry too. Until we got Patrick, I was blind to what a Guinea pig really needs. Now I'm simply trying to give them both a better life, and I'm being punished for it. I'd take them to my dads house, but he despises all rodents. I'm gonna try the introduction tomorrow when she's gone. Maybe if I can show her they can get along she'll listen to me.
You shouldn't be punished for doing a good thing. You've clearly done research to make sure you're doing the best thing you can and that's a great approach! Your mom is in the wrong in every way and I think it's awful that she tries to punish and blackmail you just so you will agree with her and she also shouldn't have disrespected you by not listening to what you had to say and allow you to present your research without instantly dismissing you.
Please know that not all adults are good people and sometimes those adults are parents. It's hard to first realize and accept that parents are just humans because when you grow up with them you look up to them and put them on a pedestal but parents don't always know best nor are they always good people. I hope you won't beat yourself up too much over this because none of this is your fault at all. I know you're in a pretty helpless situation right now since you don't get a say in anything but you might be able to take steps towards independence in the future so that you won't be in this kind of situation again.
I don't know if this is the first time your mom has done something like this or if this is a first but it sounds like this is probably not the first occurrence? My mom was very manipulative and mean as well, eventually I had to cut contact for my own sake and that was a very hard thing to do because shouldn't moms be loving and kind to their children? Unfortunately that's not always the case. It might not be that bad for you and maybe this is just a rare incident for you, at least I hope so. I don't know how old you are nor your full situation but if you ever want to talk about it feel free to PM me at any time. I might be able to give advice since I've been in that kind of situation or at the very least it might be nice to get it all off your chest, if you wanted too of course, it's fine if you don't want to and again things might not be all that bad so you might not feel the need to but the offer is there regardless.
Again, I'm so sorry this is happening to you and your pigs. I hope you will be able to talk some sense into your mom but these kind of people usually can't be reasoned with.