said by Ree:That is what I will do... thank you.
I wasn't even a customer when I got the 70% discount, I was still with Teksavvy at the time. I just said something to the effect of "I heard you're offering 70% off Ultimate internet. I'd like to sign up if that's true". The front-line CSR didn't know what I was talking about but transferred me and the second person had me signed up in no time.
So you don't really need to threaten to cancel to get a good deal. Just call to ask what the current offers are (or ask for a specific one if you've heard about one on DSLR).