My computer says it was posted yesterday, I was on from 3p-11p my time (at work, obviously not 100% active) and didn't even see it. Some don't use the main page and only go to certain forum sections and don't see it. It does not mean people don't care about new members. If I can recall correctly myself and others have posted in other threads you have started, and have been more than welcoming. Defensiveness gets you no where.
As for the mice, if you can't humanely euthanize them, I'd take them back to the apparent crappy store you got them from. To answer your question, if a mouse carries parasites or worms or diseases they can be spread to your ball python. I'd avoid that shop if it is that questionable.