well carders get victims CC from fake web-shop, hacked web-shop. only a small percentage gets info about the CCholder from his machine (except bills or smth. dunno about that much).
company DO call you sometimes to avoid fraud. if carder has CC full credit card info, he can order anything etc... if the ordered service or other thing is valuable then company calls to CCholder and asks to verify. so you have met not very good carders because they didnt know that company calls for verification. or maybe somebody who used your CC gave info to anybody after he used it.
hope this helps