@Apple fanboy - quoted below - has supplied you with an answer, an answer with which I am in complete agreement.
In essence, learn to set boundaries.
There is nothing wrong with explaining to people that you are not available for calls anytime after......and set a time after which you won't be available to take calls, - inform these people of that time - and then, enforce it.
Enforcing it means turning off your phone, or, neither answering nor responding, or, as
@Apple fanboy says, set your phone to do not disturb.
And, if they persist in phoning you at 1.00 a.m., let them know that you find this exceedingly discourteous.
Exactly.
Well said.