A failing fuel pump can screw other things, like injectors…
Not knowing that engine, but what can appear to be a failed fuel pump can in fact be a failed EDU (or ECU) controlling the pump, just a tiny solder failing inside the circuit board, if thats the case the pump might have been replaced in error.
I’ve not had a fuel pump fail but I have had and EDU go and it is just a case of just completely not working/starting because no instruction is going to the pump, rather than running or starting badly which you might expect if a mechanical component was failing.
Its also not out of the question that the pump that was fitted was a dud and that component will still carry its own warrantee. The garage should really warrantee both their diagnosis and the part fitted if they’ve taken money to do the work