At my wits end

At this point in time I'm looking for creative ideas because I'm tearing my hair out.

Situation

I recently moved and in the process I switched from a wired ISP to a wireless ISP a "WISP". My problem is that I'm having significant throughput issues and I don't know why. If I run pathping to the my DNS and to random sites on the internet I get zeros across the board. There isn't any obvious congestion or corruption. My latency is good often in the 25ms which is actually faster than my old wired connection used to be. But my actual download speeds are wildly erratic. I mean wildly. The line is supposed to be rated @ 2mps and when it is running well it can get 200K second but then it will fall to a matter of 9k second in the blink of an eye.

Things I have Tried

Replacing my AP
Used three different models of Wifi cards (two of which are Alfa's)
Moved hardware all over the place.
Switched to different channels on the AP.
Changed the MTU
Tried different antennas ranging from 5dbm to 9dbm and also got a 10 dbm directional.

(note: not in this order)

There doesn't seem to be any correlation in terms of terms of times of the day or phases of the moon but I am at the stage of sacrificing virgins. My WISP swears they are not throttling and I don't know why they would because I'm not using P2P or any encrypted traffic, just normal web stuff.

So does anyone have any clue at all. Something I might have overlooked. Any ideas no matter how esoteric are welcome at this stage.