This issue has been discussed a number of times and Bill Oliver has helpfully chimed in on the discussions with some guidance. But this is another of the variations on the theme of epee and Corps A Corps which may not appear explicitly in a search.
My previous post with links to other posts on the subject.
I will try to sum up the basic points (DownUnder has sufficiently given us the appropriate rules and sections above) I will just try to simplify.
1. CaC is not a penalty in epee. It does not annul a touch
2. CaC does halt the action in epee.
a. An action started after the CaC should not be allowed to score.
b. An action started before the CaC should be allowed to score.
c. Bell to Bell contact is not to be considered CaC
3. Jostling is not the same as CaC
a. Jostling is a penalty, any touch scored with jostling should be annulled.
b. What is considered jostling and who is at fault is up the discretion of the ref. Basic guidelines have been debated at length, the rule-book has left the definition of the jostling assumed to be self-evident.
Arguing about a point, because CaC stopped the fencing before the action or arguing whether you have been jostled or not is just not worth it. It is considered a point of fact under the observation of the ref.