There are different categories of friendship.
It sounds like this one is more superficial, not the sort who comes through in a pinch. Fair-weather friends will often ask for favors, but seldom return them. They will almost always disappoint you. The only consolation I can offer is that once they let you down a few times when you've really needed them, you can stop wasting time trying to make the relationship into more than it is. You can also limit how far you will extend for them, extending yourself for the truly valuable friendships where your efforts are appreciated & reciprocated. I had a friend who borrowed my car, asked for help moving - twice, asked for a letter of recommendation, & came to me to for comfort when her relationships went south. But when I asked her a letter of recommendation, she couldn't be bothered. When I ed needing to talk right after my mother died, she didn't pick up, so I left her a voice mail. She never ed back. This stuff only hurts for a bit, then you see things for what they are & you move on, a bit sadder & wiser. Sorry for your troubles, arghhh