TIFU By asking to use my uncle's house to use for a birthday party

So this is kind of ongoing??

Hi everyone I'm just going to make this the shortest I can do it so if anyone wants me to clarify I will.

My dad and I are both only siblings. My mom is not. Both of them turn sixty this year. (My dad had his birthday in January) My mom's is in July.

So my maternal uncle on his own is usually a kind and loving man who is always lovely, but this, and his partner (and their roommate)'s intervention is making me think that they don't really value us.

Ok, sounds stupid, but basically, last July when my mum turned 59 I asked my dad if we could ask to use my Uncle and partner and roommate's house for a surprise party (a place they use to hold most 'family' occasions), he liked it we asked to use their house in October. They accepted. (Let me be clear, I have always understood that it was their house and if they said no, of course I would've been a little upset, but I would've moved on) But no, they gave us the number of 46 people.

I clarified this number with the two of them (uncle and partner) that November by giving them my idea of a guest list, and they weren't fazed as our idea was a little under the max but counting myself, my mom, my dad, my uncle, his partner and his roommate it would make 41 people. They later backtracked to 20 people in January, and blamed us for the original number of 46 people. Then after talking to my uncle's stepdaughter (partner's daughter) realised she'd been telling other people that the maximum was 30 people.

Now we're in a massive mess as even though my uncle's house as a location has been cancelled. We've found another place, but they're mad at us for going over the original number they said they'd given us.

Now I feel really stupid for even asking to use my uncle's house in the first place.

TL;DR: My dad and I asked to use my uncle's house for a birthday party when they use it for almost every other occasion regarding his partner and roommate's families. They accepted, backtracked a couple of months later, and now we're in a he-said she-said situation and my mom is blissfully unaware of what's going on.