My gig was cancelled with no notice

Hi all you awesome peeps! I need advice. I am in a duo and 4 piece band. Our duo performed a new 5 star resort in Silicon Valley. They paid our duo $400, and each got a meal and 1 drink. 3 hour show. They said no tip jar allowed and no QR codes can be displayed. Day of, I was texted that I will be paid the following week. (First red flag). They booked 2 dates with our duo and 2 dates with our band. Our band was supposed to play this Friday, May 9. Yesterday, (May 6) I got a call, and they cancelled our show Friday and our future shows. They said they decided to go with a DJ. WTF??!! When our duo performed, EVERYONE clapped after each song and we had amazing positive feedback. I am the band manager, but I’m no pro. I book our shows, create flyers, do our website and social media. I’ve been promoting this event, and we’ve been rehearsing, and I turned down other shows because we booked with them. In the 15 years of performing, this is only the 2nd time this has happened. We had a verbal contract. We have text and email communications. Why do they think it’s OK to cancel, with no notice? I have a very limited income and am scraping by each month. I was counting on this income, and so was our band. I am so upset right now, I don’t know what to do. Any suggestions, other than, “next time get a written contract.” Any positive feedback appreciated! Thank you!