Depends on your insurance, give them a call and ask

The internet doesn't know your insurance provider or what coverage you purchased.

Assess damage and cause.

Consult a lawyer.

Insurance may cover it, and they may sue the tenant to reclaim costs. But best to ask the insurer.

I think it depends if you have land lord insurance or not.

Beyond that im listening to a video about the movie tennant so i was somewhat confused

WTF? A bag of powdered cement?

Make sure to get a second opinion just in case (10-15K is nothing to sniff at!). Some photos from a snake cam would be good too. More information will empower you.

N.B. "Tiles need to be redone" is an understatement. A proper job will involve ripping ALL tiling from the bathroom, removing all adhesives (may be easy or hard depending on what they used), probably re-rendering, re-waterproofing (ideally twice), then laying new tiles. Cheaping out on these steps can lead to earlier ones ruining later ones, requiring you to do the entire thing all over again (it's a horror).

Sounds like you need a better plumber or a better tenant

What did they pour down? Did they do so to unclog? Could a plunger or snake or camera be considered first? Had they already reported any problems to you? Has there been problems before this?

You need to check your policy as to what is covered. Blockages may come under normal wear and tear. Or it may be you need to seek costs from the tenant if they've done the wrong thing. Likewise, you may need to take from their bond etc and you may have an excess. Certainly id be getting a second opinion.