Hi!
You could try bitter apple, hot sauce, and/or purchase cord coverings or even pvc pipe depending on what all you have to try to deter your cats from.
Here's a thread with the same/similar issue and some of the suggestions; Wire Chewing
I was going to suggest something like this (see link below), but if you go through the thread Furballsmom
just gave you, it is included in there as one of the links. Cable Ties and More
So, you've bought all the different products that were noted above and in the links? Wow, sorry you spent all that money and didn't find one that worked. Did you also try the PVC pipe - if so, why didn't that work?