Elo Hell - Please help!

My friend and I play duo in ranked as ADC and support and we cannot win a game for the life of us. I'm silver 5 and he's bronze 3 (he's been playing a lot longer than me and is a lot better, so I'm not sure why I'm a few ranks above him).

We have carry potential every single game and win our bot lane more than 80% of the time, but the other lanes are so bad that we literally cannot do anything to save the team. Our most recent match featured a Zed with 10 kills after 15 minutes, while we my AD had 3 kills and no deaths, was ahead in CS, and we were nearly done finishing the bot tower. Obviously, it isn't like that everygame, but that's just an example of what we go through. Many 0/something lanes every game. Very frustrating and we need help.

I'm not expecting that I go up to gold instantly - I know it will take time. I'm just saying it's crazy how we literally lose more than 80% of games.... Judging by our skill, I'd expect to win at least 40% of our games, probably 50%. We also do not need advice like "play easier champions" or stuff like that. We know the champs we can play and play them very well. Please help!

By the way - I play Pyke and he plays a different variety of champs (mainly Lucian and Vayne, but he counter picks most of the time).