THIS ^^
I'm sorry, it's the way it is, but it is and has been quite standard for decades now.
Indigococo84 advises "buckle up for the ride." I'd go one further and say 'get your armour on and sharpen your sword.'
When their young and you've expected them to be treated fairly, and its things like it's their birthday, or coming up to Christmas etc, it does feel very emotional, overwhelming, exhausting, and impossible to battle.
But, IME if you have a child whose development issues aren't going to be simple, then it's a long haul battle through education and other services, and you're going to have to prepare for that.
Listen to IPSEA, they know their stuff. Read the SEND code of practice inside out, read the amendments as they happen, stay knowledgable. Learn it all. Knowledge is power.
Most of what they do is just standard delaying tactics, because when they do that to lots of children the sum saved (at the cost of the childrens development) is considerable. Sometimes it becomes more than delaying tactics, but right really is might when it comes to the law, even if you have to keep taking it higher.
Once they realize they are more likely to die on your chosen hill than you are, things change. They depend on capitulation.
I didn't start doing all that, until things had gone very wrong. But once I did, I learnt enough to be able to take the LA first to tribunal, then to court, then threaten judicial review to stop them continuing something nasty with others.
That's the same me that couldn't believe it or stop crying when it all first started.
I went through each process unrepresented, but had learnt and understood the law, and have found judges to be very good when you approach from that angle, and they don't like LA's dirty tricks either. The law is your friend once you learnt how to use it.
TBH I'm also "emotionally and financially exhausted" but I'll take it.