Parents ruining entire experience

I’m getting married this October but the entire experience has been ruined by my parents. When we got engaged last year, my mom had a meltdown that she wasn't included. They have always treated my fiancé like trash, and despite that he always made an effort and still asked for permission. Fast forward to this year, we’re planning a small wedding with a budget of 10k at a restaurant. The day we went to sign the contract, my parents interjected and said they want to throw us a big wedding and offered to pay for the reception. We said no, but they stressed that because they paid for my sister’s wedding, it’s only fair they do the same for me. I gave them so many opportunities to back out, saying I need to know if they can really do this or we will need to go back to our original plans. They affirmed it was all good so we moved forward.
A few months pass and save the dates are sent to 150 ppl. I involved my parents in everything because they had final say. But the tasting was the worst. Right after we finished what we thought was a good day my dad pulls us aside and says “the bill is due in two weeks. Things change and we’re not paying you’re on your own”. I was distraught, in shock. They left us with this bill they knew we weren’t budgeted for and were so mean about it. I invited more than double the headcount because they told me to. How do I not send an invite now when all these ppl are expecting it? It’s embarrassing. They also lie and said this was all our own doing.
We have to make cuts and now they’re throwing a fit that I’m not inviting kids. They just met my fiancés mom for the first time in 3 years (they had refused to meet for no reason) and told her they want no contact with her and are not decided on attending my wedding. I have a great relationship with my future MIL so Im hurt and embarrassed. My parents have been so unsupportive from the time we got engaged and routinely causing drama. They bent over backward for my sister when it was her wedding. It’s not about financial support for me. I feel short sided in every way, they even said I’m too old for a shower and it would be embarrassing (I’m 35). Nothing about this has been enjoyable for neither my fiancé nor I. He’s a great man and doesn’t deserve this from them. I’m seriously considering not allowing them at my wedding because it’s clear they don’t care about our happiness. What should I do?