YC Rejection – How much should we change to address their concern?

After 2 rounds of intense interviews, got the rejection email last night. Although we agree with YC's reason for rejection (user acquisition), we'd like to confirm that not everyone got the same response before we devote our full energy in pivoting or changing something fundamentally to deal with the issue they raised.

We are super passionate about our idea and already had planned out the milestones we need to hit in the next few months. But if we were to truly address their concern about user acquisition, we need to take a long and hard look at our business model and the overall landscape, but we fear this may jeopardize our schedule.

Anyone else feeling the same? How much are you going to change to address their concerns?