Babyshower ruined

So I’m 28 weeks and me and fiancé decided to go with his sisters girlfriend’s small business for our party planner (baby shower). His sister’s ex girlfriend recently passed away, they were together six years and current girlfriend came into the picture as “the other woman.” His sister made a post on Facebook sharing her condolences and love for the ex and her family and the girlfriend not only attacked her but then told us she is not doing our baby shower. We already paid her $1,100 to decorate and paid the venue $940/$1200. She sent us $429 back (which she said she over sent and if we don’t send $100 back she’s keeping our backdrop) she also charged us the money to rent the 360 photo booth which came out of the $1100. She did give us 25 invitations. She’s keeping all decor that’s already been purchased including charger/dinner plates, runners, balloons, etc but the venue provides tables, chairs, and linens. Y’all what are we supposed to do? This is our first baby and our shower is September 5. We paid her in full first because we thought she was family.