Only lukewarm water?

I moved into an apartment last month. I have not been able to take a hot shower since then. The water might get hot for 30 seconds then goes back to lukewarm.

What is weird is the only time the shower water was EVER hot was when the management came to check it and they turned it on and it was steaming. The only time.

Since then, it’s back to only ever being warm. I have told them this and they tell me there’s no problem because the one time they came, the water was hot. I feel like I’m losing my mind because I’m standing here right now with my hand under the water for 5 minutes and it’s just warm with the cold turned all the way off.

They keep saying it’s because I am taking a shower at “peak times” but I have tested it in morning afternoon night all the time and it’s only ever warm.

They’ve sent me an email saying they’ve checked it multiple times and “no other tenants ever had a problem” which is making me feel even more insane. The first part isn’t even true — they also didn’t “check” anything in my apartment, they just turned the water on and the ONE time he was here it was hot.

Should I just call 311? I don’t want to foster a bad relationship with the landlord because I don’t feel like and can’t afford to move even at the end of the lease but I really really wish I could take a hot shower.