Massive lag issues

Repost because "We have removed your content due to a violation of the following board rule: Adhere to Board Guidelines"

First of all, it saddens me that I have this problem, and when I report it Riot decides to completely ignore and deny it exists instead of providing any sort of help or feedback. Second of all, this "bug" (since Riot seems to not see it as a bug) makes the game completely unplayable. Constant sliding around, inability to move or cast abilities, huge delays between pressing Q and the ability actually going off, champions disappearing from the map, dead minions remaining active, dead champions remaining active, and damage not accounted for are a few of the problems that happen. Also note that during any of these lag spikes, my* ping stays exactly the same* (usually around 105). Another problem which is probably related is a massive frame rate drop, except the frame rate isn't dropping. In most cases, it actually goes up, but the screen starts to lag and jitter all over the place.

TL;DR The game is unplayable 75% of the time because it lags for no conceivable reason.