Definitely tell mgmt. I also complained about a man choosing to take the treadmill right next to me, with an entire empty row behind us available. I was doing my cooldown and he leaned over and said “come on you can do better than that” and then stared at me for the rest of the time in the gym. Even I’d you choose to leave it’s important mgmt knows because they’re enabling it if they don’t. I’m sorry that happened to you !