In laws screwed us over

We ended up losing our venue in January thanks to covid and so my fiance and I were going to book another place. But then his parents offered up their big backyard to us. So we have been planning our wedding in their backyard for a couple of months getting everything in order. So a month ago my mom started planning my bridal shower and couldn't really find any enclosed shelters. She ended up finding a shelter and booked it right away in fear of losing the spot. My mom asked me if that day and place was good, so I checked with my mother in law and she said that she was available that day. Well a couple of weeks later she tells me it's not a good day for her because she forgot about her friends kids wedding that she rsvpd to. She asked if my mom would be able to make it for a different day and I told her it would probably be unlikely because she really couldn't find any shelters for any other day. Then she asked if she could move the time, my mom said she would change the time to even earlier so she could make it to the wedding at 4pm. Well she still isn't happy and feels my mom disrespected her. And she is angry with my mom. So in return 2 months before our wedding she told us we no longer can have the wedding at her house. And she's also pissed because my parents are just paying for the cake while they are paying for catering. To be clear we have never asked anyone for help financially, we planned on doing it all on our own. We never even asked to have it in the backyard they offered it. She has been throwing a wrench into our plans since 2019 when we started planning it. Like I'm so over his parents and really don't care to have a relationship with them. Like how are you going to do that to your son 2 months before the wedding because of your feeling towards someone else.