Many GM's (at leats EU wise) are oft-tunnel visioned end-cap players so anything that goes beyond Raids is often hard to grasp for them. In my experirence your best hope is that you get one of the RP-GM's as they tend to be the most helpful, and generally a bit older/less out to flash their e-peen.
With a F2P account I wouldn't expect too much service, though, as because of that background they seem to often treat you as ''can play for free and still complaints'' (even though of course such a stance goes completely counter to the idea of F2P as a marketting tool - you want to reel those people in as P2P)
Basically keep ticketing every couple of days in case of new incidents, as this means the tally of 'camping complaints' will go up, and you'll most likely keep getting different GM's.
Points you can bring up (sprinkle your ticket at leisure) :
- they introduced the time-limit on WSG exactly to counter this kind of behaviour.
If it was a tactic to be supported, there is no reason for time-limits, especially because people don't need specific Battleground marks anymore (and hence a clear moment the game ends, to dole out the Marks).
- in the Battlechest Guides and other places (including the EU Forum post where the WSG GY change was originally announced; they later backpedaled on it a bit by saying that the GY change was only to dumb down the niche entertainment that is RBG's) , Blizzard says it frowns on GY camping and it can only 'legitimately' occur in AV as there capturing GY's is a legitimate BG objective.
So if they say ''GY/Spawn camping is a legitimate tactic in WSG' (and I would try to press them to answer wether it is in a straight manner) it's an even more legitmate question why they changed their earlier POV.
(the answer is probably because they want to market the game to atavistic troglodytes but they're not going to say that out loud ofc)
- Point out that camping is rife in the Trial bracket and ask directly wether this is the kind of game their marketting department wants to offer to people trying out their game.
Most likely they'll come up with some standard customer reply ("we don't get many tickets about this'') to which you can answer with the question if there is any data on how many try-out players are aware of the Ticket function, and how many of those PvP.
Of course, I wouldn't expect any miracles, as Blizzard /cares without limits.