First - contact whoever you purchased it from, let them know the situation and ask for help, they may know a bit about the snake and its habits before leaving their care.

Second - what do YOU know about this snakes habits before and after you acquired it? How are you keeping it? What did it eat the first and only time? What kind of carpet python is it? How big is it?

Third - you may need to try live, try to find a source of live RATS. Carpet pythons are notorious for being difficult, if not impossible, to switch from mice to rats later in life. I've never fed a mouse to any of my carpet pythons and never will.

A couple tips on feeding:

Feed at night. They are nocturnal, and I always get pretty extreme feeding responses after lights-out.

Make sure the feeder is pretty darn warm, heat signatures detected by heat pits will signal the snake to potential prey.

We have a picky BRB who feeds consistently by placing him in a tupperware (with air holes poked in it), lid on, with a thawed feeder in it. I have found the technique also works well with a picky hognose snake of mine.

Hit up moreliapythons.com, a great morelia forum with plenty of carpet python keepers. I've never had to deal with picky carpet pythons *knock on wood* so far, but you may find some carpet-specific suggestions over there from people who have had to deal with picky carpets.