Sorry to hear about your problems at the moment, I'm sure some of the more experienced users will be able to help you.
Although I would like to add that my boar Hero cage bites, but he only does it out of impatience for his food, it's mainly around feeding times he does this, but calms down
once he is fed. To me with my first two piggies I currently have, Bella my sow tends not to cage bite and doesn't even try to copy Hero. But I believe some do it to a certain degree,
in Hero's case I have accepted it as a part of his normal behaviour as it isn't in excess. Although I agree it can be rather annoying.
If it's of any help at all I have read up on the forum about guinea pigs and hate. As far as I'm aware guinea pigs don't know how to hate, the scared behaviour could be linked to their natural prey instinct,
in which they feel afraid of predators. They really don't have anything against you, they may be feeling a little nervous about something, but I can understand it can be hard to figure out why they react in
these ways.
I must say I am no expert when it comes to behaviour of piggy's but I hope some of that information might ease your mind, as I do understand what this is like.