How to deal with autofilled supports
Autofilled support players are the most toxic players you will encounter in League. They wanted to get one of the other 4 roles they know how to play and instead they're stuck on support where they feel helpless and this leads to a lot of negativity.
You can either try to carry them taking on the risk of having the autofilled support fail and drag down the adc with them, or you can swap with them taking the support role for yourself even if you don't play support.
https://www.youtube.com/watch?v=0wR2TEUlU-4
This video makes a case for when and why you might want to swap to give your team better odds of victory, without totally giving up your capacity to carry as a support, even if you don't really know how to play supports yourself.
A summary for those that don't have 4 minutes to spare
1 - An autofilled support is likely to be extremely negative, fail and drag down the adc with them
2 - It'd be a good idea to take support if it means you can avoid potentially brutal counterpicks in champ select
3 - Get some experience on Zyra, Brand, Vel'koz and Annie so that you have them as options
4 - Whenever you're faced with the prospect of picking your champ first in champ select before your counterpart on the enemy team, consider swapping with the autofilled guy so you don't have to deal with their negativity
5 - The support you pick should be AP Zyra, Brand, Vel'koz or Annie so that you retain some carrying capacity in the event that the guy you swapped with fails