Videotron and 30 days garantee

Ok so here is my very short version story. I tried to cancel my subscription last night, on the 30th day of Videotron's "30 days Satisfaction Guarantee" but couldn't do it online as I assumed I could. (isn't everything done online these days???

So having no choice but to call them, I did it this morning, on the 31st day.

Videotron is now crucifying me with a $450 fee for the Helix equipment as there is now 23 months left to the contract.

In my opinion, the 30th day ends at midnight right?
Videotron Customer Service is not available after 7pm.

So, why should I be penalized?

I am with my 30 days.

Any thoughts?

Jack