And if it is not outside Tesla's control. Otherwise the title is misleading.
The support advice given is contradictory and sounds a lot like the sort of stuff they routinely make up.
"Future update will fix it"
"Its the 3rd party network provider"
"Factory reset will fix it"
If network provider has changed the security interface if definitely wouldn't take Tesla months to reprogram for it (as support is proposing).
Its very suspicious that it "Sometimes works" and "Sometimes doesn't" - likely cause of that is an update which has been implemented in some places, and not in others. Tesla doesn't have loads of servers dotted about geographically, i.e. where the problems arise, so IMO its much more likely to be the network provider - who definitely has stuff scattered geographically.
Of course if Tesla did actually disseminate quality information, to keep their support staff properly informed, then they would be in a position to actually say where the problem lies