Yipes! Doesn't sound good. I'm wondering if a pipe broke underground and dirt got into the pipe, fed into the pump, and jammed it up. I wouldn't turn that pump on until it's been cleaned out and the impeller can turn easily by hand.

But I'm just guessing. Some pool company. Some opening. They left it like that and didn't even call you to tell you. I'd put them on my "Do Not Call" list.

Carl