Not to open door to man claiming to own building

[Mummaluelae]

I live in a block of flats above shops. Security door to enter building with intercom system.
My flat is rented via estate agents via landlord. (The only people I have names of)
The buzzer went (I assumed it was dp and forgot key)
I answered and the man said "Mr x can you let me in"
My response "sorry wrong person and address"
"No, I'm Mr x, I own the building can you let me in please I need to see xx'
" I've never heard of you or the person your mentioning sorry"
"Look I own the building and I forgot my key this is very important. Let me in"
"I can't do that as I don't know you and have never heard of you sorry" and I put down the reciever and just left him outside.

I had a peer out bedroom window (window is above main door)
I see a man standing there on the phone shouting "ffs x they won't let me in because they've never heard of me. This takes the piss"

I haven't heard anyone enter the block of flats as of yet.
Aibu?
I have 2 DC my job is to protect them. What if I let someone with a criminal record into the block ect?

Well done OP.

The representatives for the freeholder have keys. Only workman have to buzz to be let in and a few people are always aware that they are coming to fix communal things.

I hate to break it to you, it sounds like you're illegally subletting
What Tosh! All flats are leasehold, unless the various owners have bought the freehold between them. Unless it says otherwise in your lease arrangement you are perfectly at liberty to rent out the flat.

If he owns the building he should have been able to get in without relying on someone letting him in! You did the right thing and the worst thing that could happen is that you showed the landlord, if it is him, how responsible you are with allowing entry by strangers.

“YWNBU not to let him in if you didn’t feel comfortable but YABU to dramatically say you had to protect your children. I mean obviously you do yes, but I don’t think he was going to hold you all hostage on spec with a machete just because he’d got access to the building.”

This

@Andtheresaw I'm not illegally subletting thanks. I'm via an estate agents who deal with the landlord for my flat. I know my rights ect. Likewise before where I lived a block of flats my landlord was responsible for my flat and 3 others. The other flats where other landlords ect.

I know OP!
My post was a quote of a pp, with my comment correcting it underneath.

@Andtheresaw apologies!