I've got a toilet in my basement and it's leaking water from somewhere and making my bathroom tiles into sponges. I got the toilet off the bolts and this is what it looks like underneath.

I had a plumber out a few weeks back and he said they'll need to pour new concrete and I'll have to replace the tiles and grout, quoted me $3k. Thing is, a few weeks before that, I accidentally thought the toilet was leaking when the tiles were in fact seeping water from a leaking valve in the laundry room next to it. So really this toilet only started leaking after they unseated it. Did they just royally fuck up seating it on the wax ring? As far as I can tell, the flange itself is rusted but there isn't any cracks. Do I have to do all the stuff they said or just get some new silicon and wax ring? I know it's ugly as fuck but it was working a month ago.