Hello here's all the pics of my problem

Any advice would be nice

Pool store told me I should fix it this year, and the cost is about 2600 for 4 corners or 4600 for all concrete pads including removal.
This pool store has a rep of telling you a low price then jacking it up while doing the work.

Could this be a DIY project,?

Should I get it fixed ASAP?

There's also a crack in the concrete in the pool as well in the corner in the water. It sticks out about 1".