Throttle all my speed to 0

So in the past 12 months I've not gone over my threshold, this month for the first time in a long time I go over the threshold and you drop my speed from average 7.4mb/s on a 8mb line, to 0,9mb/s that's not even 1mb speed I would've thought you guys will cut it in half but to take away everything is bad ey, I'll be looking for another ISP soon.