I've replaced the fuel pump was replaced, but it doesn't work.

Make sure that the power is hooked up to the pump. Sometimes the wiring can become loose and need to be reconnected. Next, check the fuel filter. If it's clogged, it can prevent the new pump from working properly. Finally, make sure that there is gasoline in the tank. If the tank is empty, the pump won't be able to do its job. If you've checked all of these things and the pump still isn't working, then you may need to take it back to the mechanic and have them take a look. Hopefully, they'll be able to figure out what's wrong and get your car up and running again soon.