Trading champs in solo queue not working?

When I was playing a ranked game in solo queue, I got mid and was going to play Katarina, but I was the last pick so I asked my JG to pick her for me and he/she wanted to fiddle. After the JG picks kat for me and I pick fiddle, I try trading with her and she declined it, like the time bar for trading expired. I tried again and same thing happened. I went fiddle mid because the trading didn't work and I don't even remember the last time I went fid. That is one of my least played champs in the game, so i didn't know how to play. I asked kat why she didn't trade and she said she did, but declined 2 times. I don't know if she is lying or there was an error in the game, but thanks to either her or client/game, my team lost lp. This is totally unfair and I hope it gets looked into because 5 ppl lost lp that they could've won instead. Thank you for taking your time to look at this. It was very frustrating to play a champ that I don't even know against the highest scaling mage in the game, and does like 50 dmg at level 9 to normal minions.