Locked Out of My PSN Account - Sony PS4 Support Fails to Assist

Despite entering my email address correctly, I can't access my PSN account on my Sony PS4. Every interaction I've had with PlayStation support has been fruitless. For the first few days, they responded to my emails once daily and were available via phone. However, for the past three days, they've stopped responding altogether. I've informed them about the possibility of my account being stolen, but they're not treating the situation with the urgency it deserves. I've been dealing with this issue for 10 days now, with absolutely no progress.