I can call to US and Canada for free while having my GV number in Venezuela paired with GrooveIP, textPlus and other things, but what I'm trying to figure out is if there's a way i can call Greece for free and with somehow relative quality. My Star Alliance plan is Aegean so i want to find a way to call them in somewhat a reliable way. The Venezuela mobile network is worse than GV from here to place calls abroad,even if you pay you can't hear anything. I'm going to search is Aegean has an US number but I'm not sure.

Edit: Got it, i think this number would do fine (+1) 855-323-4326
As for the VPN discussion i tried once VyperVPN and it was excellent,best VPN service i've seen.