Cox agent confirms that they do throttle speeds

Just got out of a chat with an agent about speed issues I've been having for the past month and he confirmed with me that due to exceeding the data usage cap that Cox is indeed shaping/throttling my connection.  I tried to point out that under Cox's own Terms of Service it states that "Cox does not shape or throttle Internet traffic based on the particular online content, protocols or applications a customer uses" but he was adamant that I was being throttled due to excessive usage.  I had a feeling that was the case since my speeds have taken quite a nose dive in the past month.

I'm currently on the Internet Premier plan that reportedly has 100mbps/10mbps and I'm down to 16.2mbps/768kbps on my last speed test.  The download doesn't bother me so much, but the upload is killing me.  I've done some troubleshooting on my end just to make sure it wasn't Cox doing this to me.  I've moved the modem to every possible spot in the home, tried the connection with and without the router (same results either way), did a factory reset on my modem (Motorola Surfboard 6121), and checked my signal ratings and they appear to be in a good range for both the downstream and upstream.

I feel like I've covered all my bases, and the timing of my slow down with me going over my data usage really only points to shaping happening on Cox's end.  I'd love to be proven wrong, but that's what it looks like to me.  I'll probably be calling in the morning to cancel service.

tl;dr:  Asked agent if I was being throttled, said yes even though it's not Cox's policy to do so.