Did you try pumping in some water from a bucket?
If that didn't work and the pump sounded like it was running ok, lift the bucket up to a point so it is above the water connection on the utility center (with the hose still in the bucket). This can help in getting it primed. In the past I have had trouble with it priming and that helped. I haven't had any trouble with it lately when I open two faucets inside before turning the pump on.
As far as getting the pump out I have often wondered how that is accomplished. The utility center "face plate" must have to come off to gain access to it as it is right behind it and there is no way to reach up underneath to get to it.
2018 Newmar Canyon Star 3513