First time posting: I just got wrecked, then banned :(

I played a ranked match as Darius top vs riven and early made a bad play and died. I teleported right back to lane to kill her while low but she won by 1 auto attack, I realised that I would have a big disadvantage being 0/2 against the 2/0 riven. Team was like ouch shes killing you, and i replied yeah, don't come top, ill just farm under tower. That worked for a bit but she still got a lot more cs than me and would take every opportunity to kill me ex, she hit 6 went full out and killed me etc. mid insisted on ganking top but out of 3 ganks our mid syndra killed her only once, and I died each time and syndra died once. Mid would apologise and I was like its ok. Mid game riven is fed, she sees you, you're dead so i ended with a wrecked m8's score. You can read the chat, no ill feelings from me, and I said to my team my bad because I lost lane hard to the riven. My teammates saw how well she played they said shes a smurf... yet apparently someone reported me as intentional feeding and now for the first time ever playing league I am banned, 14 days it says. How can I fix this?