I've been using Jaxx for ETC for months and never faced any issue.
Anyway, you can see private keys through this procedure : https://decentral.zendesk.com/hc/en-us/articles/218375657-How-can-I-view-my-private-keys-
JAXX SUPPORT:
Why can't I send ETC out of my wallet? (I'm getting an "Error:" message!)
You may not be able to send ETC transactions if you're receiving mining rewards or if you have firewall, Tor or VPN enabled.
So... I am unable to send my ETC. I am looking for a wallet now that I can upload my private keys to. Do you guys know any that would be good for that?
Thanks!