My knowledge of things IT certainly doesn't compare with you two gents, but my experiences with Telus have made me think that Fug probably has a point.
For the majority of Telus customers, their connection being down simply means that they can't watch YouTube or keep up with the latest gossip on TMZ. That means that their response to you not having a connection will be a polite version of "just wait until tuesday, TMZ isn't going anywhere."
If I read your post correctly, you stand to lose revenue if your servers are down....and maybe customers. If I were in that situation, I would consider using an ISP where the majority of the customers were also not willing to accept down time without a very good reason...and even then, only for short periods. If the customers demand it, the ISP will deliver.