You can't be punished for having a bad game. Regardless what anyone says, if you end up feeding, but you're putting an effort in trying to win the game, you'll be fine. Doesn't matter if someone says "Oh well you're just dying over and over, you're reported." Just mute then report that player for saying that and try your best. If you're like 3/15/17 or something, you count the assist, which means you're participating and trying. And the rest of your team sees that.
There's a fine line between intentional feeding and purposely trying to lose the game simply out spite or retaliation, then there's that line in feeding but making an effort in winning, joining fights and making reasonable objectives calls. But if someone threatens to report you, you mute them and report that player for harassing you.