The fuel pump went out on my 2000 sebring - had it replaced and then one day the gas gauge stopped working correctly, i took it back to the shop and they replaced it again at n/c, but now it is not working again, why does it keep going out. and i don't know if he is going to replace it another time at n/c it wouldn't be so bad if it was always the same, but sometimes it's empty at 1/2 a tank sometime 1/4 of a tank

could possibly be the fuel sensor sending unit. might have been damaged during the fuel pump replacement.

incorrectly and half assed installed. putting a fuel pump in a chevy is very difficult and takes patients. most mechanics dont have that so go to another shop and make sure they fix the problem before you pay.

your fuel sending unit has went bad you can either replace it which is in the fuel tank (attached to the fuel pump) or wait for the fuel pump to go out

If he told you the fuel pump would correct the fuel guage, take the car back and make them fix it under warranty. I have been in the auto repair business for 21 years and if I mis-diagnose a car, I have to fix it for free to keep the customer happy.

the ground wire from the gas gauge is shorted or broken

The gas fillup should be clue, either the gas cap was not tightened enough or it is defective.

You're either looking at a short in the wire that goes to the fuel sender, or a bad fuel sender. If it was just a broken wire, it would read empty instead. The fuel sender is a permanent part of the fuel pump, so that has to be replaced as a unit.

I had previously replaced the failing fuel pump on my '98 K2500 when it went out entirely. I was ready to replace my 2000 K3500's fuel gauge as it was acting up.
When I started the engine, the gauge would bounce from the middle to way past full then back. It would also jump sporadically while driving on level ground.
I checked the electrical connections at the tank and made sure the frame ground strap located nearby was making good contact. Nothing changed until I removed the instrument panel and cleaned the connections on the back. The fuel gauge seems to be operating correctly now.
There are videos on YouTube that show how to remove the instrument cluster if in doubt. Mine dash has a pop-in plastic bezel followed by 4 screws to hold the cluster in place. It took about a half hour to inspect & clean the dash connection vs. $250 to replace the pump/sending unit combo. Hope this helps.

Keep taking it back to him until he gets it right.

Has the repair guy 'monkeyed' around with your fuel pump? If the gas guage is in the tank like most of the nowadays trucks and he bent or done something wrong with the fuel pump when he had it out then I would say he should fix it the way it should be but it sounds like you were 'taken' for a 'ride' by that mechanic!