Try holding them for more than an hour everyday. I bond with mine relatively quickly because I spend A LOT of time with them. I usually have them in my shirt for 2-12 hours a day, most days. I also try to play with them while they're awake.
Back in November I had twins come oop. A little boy named Tiny and a little girl named Quinn. Before their eyes were even open they were crabby and tried to bite. Quinn was the worst out of the two. My sister got Tiny and I got Quinn. Once she was weaned I began holding her all the time. My sister on the other hand didn't have as much time to hold Tiny. Tiny still crabs and bites. Quinn is a sweet heart who rarely crabs.
What I'm trying to say is that there is still hope. Just hold them more and hopefully they'll stop crabbing and biting. I'm not guaranteeing this will work because every glider is different. I'm just saying it worked for me on all four of my gliders. Hopefully it'll work for you.