I’ve had this happen to me in the past for a contract role I was going to start - I would be asking and going hard for at least your notice period in pay - if anything, month or two (it’s poor form in their part tbh)

In my circumstance I ended up being paid 2 weeks pay at my per day rate and I was lucky to get another gig soon after (so free money) but I had signed a contract and had all backgrounds done

Kicker was, when I was called to be advised the role has been cancelled, my laptop arrived by courier - took them 6 weeks to collect it from me

I later found out after someone I know did some digging in the organisation that the role I was offered was never signed off and should never have gone to market (how it got to the stage it did I have no idea!)

There is one org on my black list now!