Worst yet simplest way I got escalated was with Rockstar Games and I had to kinda somewhat threaten them.
I had found a kind of dangerous security issue what was being exploited (that already cost rockstar games thousands) and I tried to contact them. It took 2 months to get a response of "Thank you for supplying the info" (I only added 2 screenshots proving that I had that info and stated that I wanted to be escalated to someone who can take action).
I replied that I'll release that info online if I don't get a response in a month and that security team can get it there if they want, and…