When I go support, rarely anyone helps me

I noticed a little pattern while playing League of Legends. Every time I go support and go bottom, nobody helps me and I'm stuck fending for myself against 2 enemies. It's mostly when I go support but only sometimes when I play a champion that can kill a lot. So, how do I deal with being a support champion, without anyone else's help, because my attacks are generally pretty weak? Do I just go to another lane like top or mid, or what? When I ask for help on bottom lane, nobody listens.