“Grow up and move on?” That’s a mean response.
The same happened to me not long ago; take heart that old employers don’t share much with new ones and YOU are in control of the narrative.
In my case what I did was reached out to a colleague who wrote me a stunning recommendation letter.
I, too, was never told what had happened or why I was let go, and I was devastated.
It was a 6 month assignment for goodness sake. My husband worked 9.5 yrs as mgmt employee. Drive 140 mi a day roundtrip to work. Let go no notice so they would not have to pay full pension. They do this all the time. And contractors are at bottom of food chain and first to be cut with budgets.