If your going to order it off the internet then just get the Clacium+ from rephashy. I mean, its a 3 in 1. It has the Calcium, D3 and the Vitamins you need. easy to feed aswell. Cheap also.
Honestly, I understand if you have a hard time finding calcium without D3. All my local pet stores didn't carry it, and i had a even harder time finding reptile vitmains without D3. I eventually just ordered from lllreptile.com or another reptile site. Good luck.