For Android phones, it is the carriers that pushed the OS updates. You could either get a non-carrier based phone like Nexus or Google Edition version phones or root your phone. Then you get to control when or if you want to update the OS.

For the extra contacts, you could filter and not display "other contacts". You could even delete them from time to time. I don't know which Android phone you got, but on the Galaxy line it is very easy to control your contact list.