Best way to get enough calcium is to stop leaching it from your body by eating too much meat (that includes chicken and fish too). Humans can technically eat meat, but it takes resources away from our body to do so (namely calcium). Cows can technically eat meat as well (and disgusting enough, they are often fed dead cows), but they weren't meant to.
For more info, read:
"Mad Cowboy: Plain Truth from the Cattle Rancher Who Won't Eat Meat" by Howard F. Lyman
"Dying to get well" - Shelley Keck