I wasnt sure how long one full carto ACUALLY would last? (i know the sites say more then it always is.)
I've found that the opposite is true. My theory is they say its less so they can sell more. But i'm pretty cheap, and clean mine out once or twice before throwing them out.
If you are having trouble pulling up the juice in a syringe, either you have a tiny needle, or the juice is very very thick, or its one of those plastic needles, those suck. If the juice is thick, that could be the problem. I went through the thread, I don't remember seeing what juice it is, a high vg mix would be a problem for cartos, especially ones that have trouble absorbing juice normally. If you want to give the syringe another go, just pull out the plunger, fill it manually, watch for leaking out of the needle, and reinsert the plunger when the needle is in your juice bottle. Seeing everything you tried... i'd guess they are just junk cartos. If you ordered some with your volt battery, hopefully they will do the trick for you.
If you need to get these to work, might want to try the taryn spin to fill them. Works well to force the juice down. Well you'll see in the video.
The Taryn Spin 2011....Everything You Need To Know - YouTube (credit to taryn, who is a member here from what i understand, and teamkr808)
In a pinch, you can just use a little baggy or two, and a shoelace. I don't remember if the video shows it or not, but you can do a reverse version of this if you want to try to save the juice from any bad cartomizers.