What do I do in this situation?

Playing against ezreal yuumi as tahm kench support and cait adc....

Ezreal uses his phase shift to go in and poke cait, i turn around and go in, the fight lasts atleast 6 seconds before i realize cait still hasnt done anything (not a single auto despite literally being within auto range) and im dead after getting ezreal down to half health by myself.

Then cait goes in (walks even closer to them) then walks away and dies without even autoing back.

Based on this scenario , caitlynn was probably lagging, she didnt ping me to not go in or anything and she goes in by herself after im already dead then immediately just walks away from them and dies.

So i do my best to go around the map and snowball the team since caitlynn was apparently lagging, I gave it my best shot to snowball my team, yet in the after game lobby the enemy team is saying that I need to be reported? But I was doing my best despite the lag mechanic that was in place and nobody on my own team was yelling at me to go back botlane?

So what was I supposed to do in this situation?

This was a plat 3 ranked game btw.